SEMICENTENNIAL PUBLICATIONS 



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UNIVERSITY OF CALIFORNIA 




1868-1918 



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MISCELLANEOUS STUDIES 

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AGRICULTURE 

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BIOLOGY 



UNIVERSITY OF CALIFORNIA PRESS 

BERKELEY 

1919 



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CONTENTS 

Pages 
A Synopsis of the Aphiditlae of California, by Albert 

F. Swain 1-221 

Mutation in jMatthiola, by Howard B. Frost 223-333 

Ocean Temperatures, their Relation to Solar Radiation 

and Oceanic Circulation, by George F. McEwen 335-421 

Changes in the Chemical Composition of Grapes during 
Ripening, by F. T. Bioletti, W. V. Cruess, and H. 
Davi 423-450 



A SYNOPSIS 

OF THE 

APHIDIDAE OF CALIFORNIA 



BY 

ALBERT F. SWAIN 



[University of California Publications in Entomology, Vol. 3, No. 1, pp. 1-221, pis. 1-17] 



A SYNOPSIS 

OF THE 

APHIDIDAE OF CALIFORNIA 



BY 

ALBERT F. SWAIN 



CONTENTS 

PAGE 

Introduction 2 

Classification 4 

External anatomy 5 

Biology 8 

Economic considerations 9 

Synopsis 10 

Family Aphididae 10 

Subfamily Aphidinae 11 

Group Callipterina 12 

Tribe Phyllaphidini 12 

Tribe Callipterini 16 

Tribe Chaitophorini 32 

Group Laclinina 39 

Tribe Pterocommini 39 

Tribe Laclmini 43 

Group Aphidina 52 

Tribe Macrosiphini 52 

Tribe Apliidini 87 

Subfamily Pemphiginae 138 

Group Hormaphidina 139 

Group Pemphigina 140 

Group Schizoneurina 147 

Group Vaeunina 150 

Subfamily Phylloxerinae 151 

Group Chermisina _ 151 

Group Phylloxerina 152 



2 MISCELLANEOUS STUDIES 

PAGE 

Appendix 1. Keys to the genera and tribes of Aphididae ; a translation from 

P. Van der Goot 154 

Appendix 2. Host plant list _ _ 159 

Addenda _.. 178 

Explanation of plates 180 

Index to genera and species 215 



INTRODUCTION 

In recent years considerable attention has been paid to the 
Aphididae in the United States, and in Europe as well, and a large 
amount of literature is the result. In California, "W. T. Clarke was the 
first to make any systematic studies of these insects and his paper, 
published in 1903, embodies the results of these studies. He listed 
forty-three species, ten of which were described as new. Two or 
three of his new species are known at present, but the remainder are 
unknown. Unfortunately his collection was destroyed in the eartli- 
quake of April, 1906, so now it is practically impossible to determine 
his new species .with any degree of accuracy. Following this, there 
was a period of six years in which there were no publications con- 
cerning the Aphididae of California, except some economic bulletins 
from the Experiment Station. In 1909, both B. 0. Essig and W. M. 
Davidson published the results of their earlier studies. Since then 
both have added papers occasionally. During 1912 and shortl.y before, 
Harold Morrison made an extensive study of the species in the vicinity 
of Stanford University. He has kindly placed a report of his studies 
in the author's hands, with permission to publish the records in tliis 
paper. The author has been studying the Californian species con- 
tinuously since 1914. 

At present there are about one hundred and eighty species known 
to occur in California. This number will undoubtedly be greatly 
increased as further studies are made, since to date only a compara- 
tively small part of the state has been covered by collectors. Very 
extensive collections have been made in Ventura County and in the 
vicinity of Pomona College, Los Angeles "County, by Essig. The San 
Francisco Baj^ region, particularly in the vicinity of the Universit}' 
of California and Stanford University, has been carefully surveyed 
for aphids, collections having been made by Clarke, Davidson, Essig, 
Morrison, Ferris, and the author. Davidson, Clarke, and Essig have 
made a few observations in the Sacramento Valley, particularly in 
Placer and Sacramento counties. The author made a number of 



.4 SYNOPSIS OF THE APHIDIDAE 3 

observations in the vicinity of Fi-esno during May and June, 1915, and 
more or less extensive observations and collections during 1916 and 
1917 in San Diego, Riverside, Orange, Los Angeles, and San Bernar- 
dino counties. In addition to these, reports come to the College of 
Agriculture occasionally from tlie State Insectary and the various 
countj' horticultural commissioners. A summary of the above state- 
ments shows that extensive collecting has been done onlj' in the 
territory adjacent to San Francisco Bay, and throughout southern 
California. The whole northern half of the state, the great interior 
valleys of the Sacramento and San Joaquin rivers, and the desert 
sections of the southeastern part of the state are as j'et unexplored. 
Undoubtedly many interesting species will be found in these parts. 

The author wishes to express his appreciation of the aid rendered 
by various people during the past three years of study. To Harold 
Morrison of the Federal Board of Horticulture is due especial thanks 
for his assistance during the early part of the author's study, for his 
collection notes, and for the use of his extensive collections of Stanford 
Univei'sity vicinity and Indiana ; to E. 0. Essig of the University of 
California for his continuous advice and assistance, for the use of 
his large collections of Californian species, and for the reading of 
this manuscript; to W. M. Davidson of the Bureau of Entomology', 
U. S. Department of Agriculture, for his many notes and deter- 
minations and for the use of his collection ; to A. C. Baker, J. J. 
Davis, C. P. Gillette, A. S. Maxson. E. M. Patch, and H. F. Wilson 
for their many determinations and suggestions ; to R. W. Doane of 
Stanford University for the permission to work over his collection 
of Utah aphids and for permitting his students to use the keys included 
in this paper, thereby finding the weak points in the keys; and finally 
to G. F. Ferris of Stanford University for collections and advice. 

Ill this paper tlie author has brought together all the present 
records of California Aphididae. He has included keys for the 
determination of the subfamilies, groups, genera, and species, together 
with such illustrations as are necessary for an understanding of the 
keys. The discussion of each species includes a bibliography of the 
California literature (exclusive of the merely economic and popular), 
together with a citation of the original description and the best 
available description, a list of host plants and localities, and a dis- 
cussion of the synonomy, life history, and habits so far as they are 
known. The descriptions of certain species are not readil.y accessible 
and of others not at all adequate. Such species have been redescribed 



4 MISCELLANEOUS STUDIES 

by the author in so far as it was possible to obtain specimens. Inci- 
dentally it may be stated that the author has personally collected by 
far the larger number of the species recorded in this paper. In other 
eases the fact is noted. A host plant index (appendix 2) is also 
included. 

The sj-stem of classification followed is the one most generally 
accepted by American aphidologists at the present time. The keys 
to the species have been formulated by the author, those to the genera 
and higher groups have to a large extent been adapted from other 
workers, particularly Wilson and Essig (Aphidinae), Borner (Phyl- 
loxerinae), and Tullgreu (Pemphiginae). The papers of Baker, 
Clarke, Davidson, Davis, Essig, Gillette, Oestlund, Patch, Pergande, 
Williams, Wilson, and other American aphidologists have been found 
invaluable. Of the works of the European aphidologists, those of 
Borner, Buckton, Del Guercio, Koch, Mordwilko, Tullgreu, and Van 
der Goot have been in constant use. The classification suggested by 
Van der Goot ("Zur Systematik der Aphiden," in Tijdschrift vom- 
Entomologie, vol. 56, p. 1913) has proved interesting, and although 
the author has not felt at liberty to accept it in full, a translation of 
his keys to the groups and genera has been included herewith (appen- 
dix 1), which, it is hoped, will be of assistance in the making of 
determinations. 

CLASSIFICATION 

The Aphididae belong to the order Homoptera, being closely 
related to the Psyllidae, or jumping plant lice, the Aleyrodidae, or 
wliite flies, and the Coccidae, or scale insects. The Aphididae, or 
plant lice, are small, soft-bodied insects, ranging from less tlian one 
to five or six millimeters in length. Typically there are four forms : 
the apterous and the alate viviparous females, and the sexual forms, 
the oviparous females and the males. There is considerable variation 
from the above in different groups and species, as will be pointed 
out under the discussions of the various species. The alate viviparous 
females are the individuals most commonly taken by the collector and 
the ones that usually show the best characters for determinations. 
In the keys in this paper all characters refer to the alate viviparous 
females (the alates) unless otherwise mentioned. 



A SYNOPSIS OF THE APHIDIDAE 5 

EXTERNAL ANATOMY 

The body^ consists typically of three divisions, the head, thorax, 
and abdomen. In the apterous forms the mesothorax and metathorax 
are closely fused with the abdomen, while the prothorax and head 
are distinct. In the alate forms the mesothorax and metathorax are 
fused together and appear as a distinct division, the body appearing 
to consist of four divisions, viz., the head, the prothorax, the meso- 
thorax and metathorax, and the abdomen. 

The head bears a pair of compound eyes, usually three ocelli, a 
pair of three to six jointed antennae, and the beak. Of these, the 
antennae show the best characters for determinations, not only of 
species but of higher groups. They are either mounted on distinct 
tubercles (Macrosiphini, certain Callipterini) or appear to arise from 
the front of the licad. They consist of from three to six segments, 
the terminal one of which is usually provided with a projection or 
spur. They are six-segmented in the Aphidinae (except Essigella and 
Cerosipha), five- or six-segmented in the Pemphiginae (except in the 
stem mothers of certain genera), and three-segmented in the Phyl- 
loxerinae (except in Chermisina, in which the alate forms have five- 
segmented and the sexual forms four-segmented antennae). The 
spur of the terminal segment maj' be equal to or longer than the 
segment (Aphidinae, in the Macrosiphini it attains its greatest length, 
often being as much as ten times the length of the base) ; it may be 
merely a short thumblike process (Pemphiginae, Laehnini, and cer- 
tain Callipterini) ; or it may be apparently lacking (Phylloxerinae). 
The two basal segments are always short, and quite regular in all 
species. The remaining segments show the greatest diversity, par- 
ticularly in number, size, and shape. Sensoria are always present on 
some of the segments. There is one primarj- sensorium always present 
at the distal end of the terminal segment, and when the antennae con- 
sist of more than three segments, one also at the distal end of the 
penultimate segment. These sensoria are fairly large and clear (some- 
times furnished with a hairy fringe) and are more or less circular. 
The accessory sensoria are a group of small indistinct sensoria, which 
number from three to six, and which are located in close proximity 



1 Por a fuller discussion of the external characters consult the followinfc 
papers: Vickerey, R. A., A comparative stutly of the external anatomy of plant 
lice, 12th Kept.' Minnesota State Entomologist 1908 ; Sanborn, C. E., Kansas 
Aphididae, Kansas Univ. Sci. Bull., vol. 3, 1904; Mordwilko, Alexander, Keys to 
the groups and genera of the Aphididae, Ann. Mus. Zool. Imp. Acad. Sci. St. 
Petersburg, vol. 13, pp. 3fi2-3l'.4, 1908. 



6 MISCELLANEOUS STUDIES 

to the primary sensorium on the terminal segment. Secondary sen- 
soria are usually present in the alate forms, but oftentimes absent 
in the apterae of certain species. When present they are always on 
the third segment, but in antennae consisting of five or six segments, 
they ma.y be present upon the fourth, fiftli, and even sixth segments. 
In the Pemphiginae they are arch-like or half rings, or form complete 
rings about the segments. In the Aphidinae they are circular, oval, 
or transversely linear, but are never rings or half rings. The shape 
and number vary considerably, and are of specific importance. The 
number maj- vary from as few as tliree or four {MyzocaUis maureri 
Swain), to as many as forty to fifty on the third segment, and many 
also on the fourth and fifth {Myzns hraggii Gillette). Unfortunately 
these highly important characters were overlooked or not taken into 
consideration by the earlier workers. The beak is four-jointed and 
seems to arise from between the fore legs. It is always present (except 
in the sexes of certain of the Phylloxerinae), but is seldom of specific 
importance (except to distinguish Aphis baker i Cowen from Aphis 
senecio Swain, and in certain of the Lachini). It may be very short, 
as in Aphis hakeri Cowen, where it reaches only slightly beyond the 
first coxa, or it may be very long as in Stomaphis, where it is from 
one and one-half to two times as long as the body. In leaf-feeding 
species it is u.sually sliort, while in bark-feeding forms it is longer. 
This is naturally necessary, for those that live on thick bark must have 
a longer beak in order to reach throiigh to the plant juices. 

The thorax consists of three divisions, the last two of which are 
usually more or less fused together, and considered as one ; the two 
divisions being called, in this paper, the prothorax and the thorax. 
On the lateral margins of tlie prothoi'ax there is sometimes a pair of 
small tubercles. These are not present in all species, however, and 
they differ considerably in size in the various species. There are 
three pairs of fairly long and slender legs (except in Phylloxerinae. 
where the legs are greatly atrophied, approaching those of the 
Coecinae in size). Typically the legs consist of four joints, the 
coxa, the femora, the tibia, and the tar.sus. In some genera the tarsi 
may be atrophied {Atarsos, Mastapoda). The comparative lengths 
of the first and second segment of the tarsi are sometimes of generic 
importance (Laehnini), and the comparative lengths of the hind tarsi 
and the cornicles are oftentimes of specific importance (Aphis, Ptero- 
cmnnia). A small empodial hair is found between the claws in the 
Aphidinae. In the Callipterina it is leaf-shaped or spatula-like. In 



A SYNOPSIS OF THE APEIDIDAM 7 

the Aphidina and Lachnina it is hair-like, usually being as long as the 
claws (except in the Pterocommini, in which it is considerably 
shorter than the claws). The wings are membraneous and hyaline 
(except in certain Callipterini, Lachnini, and Macrosiphini), and are 
held roof-like over the body when at rest (except Moncllm, Phyllox- 
erinae, Hormaphidina, in which they lie flat on the abdomen). The 
veins of the fore wings are as follows: the costal and subcostal are 
almost parallel with the anterior margin; the radial extends from 
the posterior margin of the stigma to the outer margin of the wing, 
being either curved or straight ; the discoidals, three in number, extend 
from the subcostal to the posterior margin of the wing. The outer 
or third discoidal {media, cuhitus of some authors) may be simple 
(Hormaphidina, Pemphigina), absent (Phylloxerinae), once-branched 
(Schizoneurina), or twice-branched (Aphidinae, except Tox.optera). 
On the anterior margin of the fore wing is a dusky spot located be- 
tween the wing margin and the subcostal veins, and between the 
distal ends of the costal and subcostal veins, known as the stigma or 
Pterostigma. It is usuallj' trapezoidal in shape, and does not extend 
to the tip of the wing (except in Longistigma and Mindarus, in which 
it reaches well beyond the tip of the wing). The hind wings have 
one longitudinal and either one or two transverse veins.- In the 
Pemphiginae and Phylloxerinae dorsal wax glands are sometimes 
present on the thorax, in which ease their number, shape, and posi- 
tion are of more or less specific importance. 

The abdomen consists of nine more or less similar segments. The 
coloration of the various segments, especially in species in which the 
color is variegated, is sometimes of specific importance. In certain 
species wax glands are present on the abdomen (Phylloxerinae, and 
particularly the stem mothers of Pemphiginae) and may be of use 
in making determinations. In the Aphidinae the presence or absence 
and location of small lateral and dorsal tubercles are often important. 
The anal segment consists of an anal plate and a cavida. The cauda 
may not be .separated from the abdomen (Pemphiginae, Lachnina), or 
it may be short and conical (Aphidini), short and globular, being 
constricted in the middle (Callipterina), or it may be long and 
ensiform or sickle-shaped (Macrosiphini). The anal plate is usually 
well rounded, being half-moon-shaped, or it may be emarginate or 
bilobed (Callipterina). On the sixth (or fifth?) segment is a pair 



2 For a full discussion of the venation see Patch, Edith M., Homologies of the 
wing veins of the Aphididae, Psyllidae, Aleurodidae, and Coccidae, Ann. Eutom. 
Soe. Am., vol. 2, pp. 101-13G, June, 1909. 



8 MISCELLANEOUS STUDIES 

of short tubular processes, the coruieles (honej' tubes, nectaries of 
some authors). These are quite valuable characters, both specific and 
generic. In the Phylloxerinae and most of the Pemphiginae they are 
lacking, but in the Aphidinae they are always present, and show a 
great diversity of form. They may be merely pores (certain Callip- 
terini, Ccrosipha cupressl Swain, Lachmis taxifolm Swain), they may 
be cj'lindrical, yet quite short (certain Callipterini, Chaitophorini) ; 
they may be short and cylindrical or conical (Aphidini) ; they may 
be truncate, cone-shape (Lachnini) ; they may be clavate and long 
(certain Callipterina, Pteroeommini, Maerosiphini) ; or they may be 
long and cylindrical (particularly in Macrosiphum and 3Iyzits). 

BIOLOGY 

Considerable variety is exhibited in the habits, life liistory, and 
methods of reproduction, as well as in the structure and body form. 
Reproduction is almost entirely parthenogenetic, although certain 
species at certain times have a sexual rei^roduetion. Fewer species 
have sexual reproduction in California than in colder climates, due 
to the fact that mild weather throughout the winter permits them to 
live over, and hence tlie eggs are unnecessary. Many species produce 
generation after generation parthenogenetically, and are most abun- 
dant in the spring and early summer, but gradually disappear toward 
midsummer, due partially to their predaceous and parasitic enemies, 
and partially, undoubtedly, to the heat of the summer. Other species 
regularly produce sexual forms in the fall, which lay eggs that hatch 
the next spring. The forms hatching from the eggs are wingless 
(except in Callipterini) and usually of a different form from the 
later generations, and are known as the fundatrix or stem mother. 
The fundatrix is alwaj'S viviparous. Her progeny consists either of 
all apterous or partly apterous and partly alate viviparous females 
(fundatrigenia), which in turn produce other generations of funda- 
trigeniae. The last asexual generation in the fall, which gives birth 
to the sexual forms (sexuales), are known as sexupara, and are usually 
alate. Oftentimes in the second or third and even fourth generation 
there is a definite migration from one species of host plant to another, 
where the aphids live over the summer (virgogenia), the sexupara 
returning to the original species of host in the fall to give birth to 
the sexuales, which lay their eggs there. Aphis nvalifoliae Fitch rep- 
resents an example of this habit, the winter host being apple, the 
summer plantain. Oftentimes the fall migrants (sexupara) of certain 



A SYNOPSIS OF THE APEIDIVAE 9 

species differ considerably in structure from the spring migrants 
(fundatrigenia). This is particularly noticeable in the Pemphiginae. 
Many species are confined throughout the season to one species of host, 
others to one or two or a few species, while still others may live on 
any of a number of hosts (Aphis senecio Swain, Rhopalosiphum per- 
sicae (Sulz.)). All sustenance is derived from the plant juices of 
the various hosts, but each species is usually confined more or less 
definately to feeding on some certain part of the plant. Some live 
entirely upon the leaves, some on the stems of the leaves and small 
twigs, some on the trunks and larger branches, some on the roots, 
some on the flower heads and racemes of the host, and still others 
feed on almost any part of the plant. The greater number of species 
are free living, but certain of the Aphidinae form pseudogalls (Aphis 
pomi De Geer, Aphis nmlifoliae Pitch, Phyllaphis coweni (Cockerell) ), 
while the Pemphiginae and Chermisina form true galls. Nearly all of 
the Pemphigina spend at least part of the season on various species 
of Populus, the Schizoneurina on UIiiius, while the Lachnini and 
Chermisina are practically confined to the conifers. The Ajihidinae 
are found mostly on deciduous trees and herbaceous plants, although 
some live on conifers (Myzaphis abictinus (Walker), Nectarosiphon 
morriscmi Swain). 

ECONOMIC CONSIDERATIONS 

From an economic standpoint most of the species are of no 
importance, although there are manj' that are well known pests of 
cultivated crops. For example the woolly apple aphis (Eriosoma 
lanigera) is a world-wide pest of considerable importance to the apple. 
The green and the rosy apjile aphis (Aphis pomi, A. malifoliae) do a 
large amount of injury in certain localities, and are extremely difficult 
to control. The rose aphis (Macrosiphum rosac) is known the world 
over, and although living unprotected and easily killed with any of 
the common contact insecticides, it is recognized by everyone who has 
grown roses in the doorj'ard as an extremely troublesome pest. The 
walnut aphis (Chromaphis juglandicola), the cabbage aphis (Aphis 
brassicae) , the green peach aphis or greenhouse aphis (Rhopalosiphum 
persicae) are all well known pests. The common contact insecticides 
are usually efficient for their control. Many species are kept well 
in check by their predaceous and parasitic enemies, the ladybirds, the 
syrphid flies, the laeewings, and the braconids. Of the ladybirds, 
probablj^ the most efficient in California are Coccinella californic<i 



10 MISCELLANEOUS STUDIES 

Mann., Hippodamia convergens Guerin, and Scymnus nehulosns Le- 
conte. Of the syrpliid flies, those consuming the largest number of 
aphids and the most abundant in the state^ are Catabomba pyrastri 
Osten-Sackeu, Allograpta oMiqiui Say, Syrphtis arcuatus Fallen, S. 
amerlcanus Wied., 8. opinator Will., and Eupeodes volucris Osten- 
Saeken. Chrysopa calif ornic<i, Coq. and Sympherobms angustus Banks 
are the most important aphid enemies among the lacewings. Among 
the Braconidae there are two very common species in California, 
Lysiphlebus tcstaccipes Cressou and Diaretus rapae Curtiss. Others 
have been reared by the author and will be mentioned later. The 
author wishes to thank Dr. L. 0. Howard and Mr. A. B. Gahan of 
the Bureau of Entomology for their kindness in identifying the 
various hymenopterous parasites of aphids sent to them. 



SYNOPSIS 
Family Aphididae Passeriui 

Passerini, Gli Afidi, 1860. 
The family Aphididae Passerini is divided into three subfamilies 
(following Alexander Mordwilko), which are: Aphidinae Buckton, 
Pemphiginae Mordwilko, and Phylloxerinae Dreyfus. Van der Goot 
considers but two subfamilies: Aphidinae v. d. G. and Chermisinae 
V. d. G. His subfamily Aphidinae includes both the Aphidinae and 
Pemphiginae of Mordwilko, while his Chermisinae is the same as 
Mordwilko 's Phylloxerinae. Following is a translation of Van der 
Goot 's descriptions of the two subfamilies : 

Subfamily Aphidinae v. d. G. : Body very often without distinct jiroups of 
glands for the secretion of wax. Antennae usually six- or seven-jointed [when 
the terminal process of the sixth segment is longer than the segment he considers 
it as the seventh segment]. Only in a few cases are the apterous forms with 
three-segmented antennae. The primary sensoria usually have a distinct "haar- 
kranz" [hairy fringe?]. Cornicles almost always and eauda often present. Pore 
wings with four veins, the cubitus or media I very often divided: hind wings 
usually with two cross-veins. Vivi-oviparous: the sexuales mostly of the usual 
form. 

Subfamilj' Chertnisinae v. d. G. : Body almost always with distinct groups of 
glands for the production of wax. Antennae three-segmented, often evidently five- 
.segmented. Sensoria always without ' ' haarkranz. ' ' Cornicles always absent. 
Fore wings with three veins; hind wings with only one small vein. Always only 
oviparous: sexuales dwarfish, with or without beak. 



3 Davidson, W. M., Syrphidae in California, Jour. Econ. Ent., vol. 9, pp. 454- 
457, 1916. 



A SYNOPSIS OF THE APHIDIDAE 11 

The latter subfamily has been cousidered by the author as Phyllox- 
erinae Dreyfus; the former as two subfamilies, Aphidinae Buckton 
and Pemphiginae Mordwilko. Mordwilko gives the following char- 
acters for these two subfamilies : 

Subfamily Pemphiginoe Mordw. : Antennae of the alate forms five- or six- 
segmented, the third bearing a specifically definite number of transverse or arch- 
like sensoria; sliort, usually not longer than the head and thorax. The apterous 
parthenogenetie females have four- to six-segmented antennae, but these ar(i 
sometimes reduced to three or even to two segments. The fore wings of the 
alate forms have four transverse veins, of which the third or cubital vein [third 
discoidal] is either simple or once-branched. The hind wings have one or two 
transverse veins. The cornicles are either entirely absent or very slightly devel- 
oped, and in the latter case may not be present in all the forms of one sjjecies. 

Subfamily Aphidinae Buckton: Antennae always six-segmented, except in the 
stem mother of some species, and in the genus Sipha Passerini. [This genus is 
not represented in California. In EssiffcUa Del Guereio, Ccrosiplta Del Guercio, 
and Trifidaphis Del Guercio, three Californian genera described since the publi- 
cation of Mordwilko 's paper, the antennae are but five-segmented.] The last 
antennal segment often ends in a long thread-like filament which may be longer 
than the segment. Antennae with a long filament are mostly from half the 
length of the body to longer than the body. The antennal filament is character- 
istic only for this subfamily ; some genera of the groups Lachnina and Callipterina 
have a very short filament, and the antennae are not longer than the head and 
thorax. The sensoria are small and are shaped like dots, circles, or transverse 
holes, but never archlike or half-rings. Segment 3 bears the largest number, 
especially in the alate forms. The cubitus [third discoidal] of the fore wings is 
usually twice-branched although there are some exceptions, as Toxoptera Koch. 
Most species have long cylindrical cornicles which are often clavate in the middle. 
Sometimes they may b'e greatly reduced or poorly developed, and, as in Lachnina 
and Callipterina, they may be replaced by cupola-shaped elevations. A cauda 
is usually present, being cdnicle, ensiform, or globular, although in Lachnina it is 
not evident. The sexual forms have beaks, and become quite large. 



Subfamily Aphidinae Buckton 

Buckton, Mono, British Aphides, 1883. 

This subfamily is divided into three groups, following Carl Borner 
(Sorauer, Paul, Haudbuch der Pflanzenkranklieiten, vol. 3, p. 664, 
1913). Borner considers the family Aphididae as a superfamily, and 
divides it into four families ; so this subfamily Aphidinae he considers 
a family, and the various groups as subfamilies. Below is a trans- 
lation of his key : 

1. Claws with spatula-like or leaf-shaped empodial hairs (fig. 1). Cornicles vari- 
ously formed, bare. Pubescence of larvae as in Aphidina. The majority 
of the species live free and monophagous on trees, only seldom on herbaceous 

plants, and never migrate collectively Group Callipterina 

— Claws with simple empodial hairs (fig. 2), often hard to see 2 



12 MISCELLANEOUS STUDIES 

2. Antennae with short terminal joint (fig. 3), (except in Pterocommini, but then 
the Cauda is not tail-like). Body ridges with more than six longitudinal 
rows of hairs. Hairy covering mostly thick. Cauda not lengthened tail-like, 
anal plate widely rounded (fig. 5). Wax glands either present or lacking. 
Mostly strongly monophagous forms, at times of remarkable size. Pound 

mostly on tree growths and without change of hosts Group Laclmina 

— Terminal joint of antennae always with a long, slender filamentous projection 
(fig. 4). Body ridges of young larvae at most with only six longitudinal 
rows of hairs, which may be increased after the first molt. Cauda either 
short or lengthened tail-like, anal plate widely rounded (fig. 6). Species 
monophagous or polyphagous, many with a change of host plants. On 
tree or herbaceous groivths Group Apludina 



Group Callipterina Morel 
(Subfamily Callipterinae Borner) 

Mordwilko, Ann. Imperial Acad. Sci., St. Petersb., 1908. 

Borner, in Sorauer, Handbuch der Pflanzenkrankheiten, vol. 3, p. 664, 1913. 

According to Borner tliis group consists of two tribes, the Phyl- 
laphidini and the Callipterini. lie divides the Callipterini into two 
groups, the Callipterini and the Chaitophori. The author has followed 
him to a certain extent, but has given each of the last two groups equal 
rank with the Phyllaphidini, and thus considers this group, Callip- 
terina, as consisting of three tribes. Below is a key to the same : 

1. Wax glands with faceted pore fields present. Antennae as in Lachnina 

(fig. 13). Pubescence delicate Tribe Phyllaphidini 

— Wax glands lacking or without faceted pore fields. Pubescence often very 

remarkable. Terminal joint of the antennae often lengthened into a bristle 
(fig- 30) 2 

2. Anal plate more or less emarginate or bilobed (fig. 7), except in Euceraphis 

Koch Tribe Callipterini 

— Anal plate widely truncate or rounded (fig. 8) Tribe Chaitophorini 



Trilie Phillaphidini Borner 

Borner, in Sorauer, Handbuch der Pflanzenkrankheiten, vol. 3, p. 664, 1913. 

This tribe Phyllaphidini consists of but one genus, Phyllaphis 
Koch, which is represented in California by three species. 

1. Genus Phyllaphis Koch 
Koch, Die Pflanzenlause, p. 248, 1857. Type Aphis fagi Linn. 
Key to CALiroRNiA Species 
1. Alate viviparous females unknown. Wing venation of alate males similar to 
that of Eriosoma spp. (fig. 17). Forming pseudogalls on edges of leaves 
or living free in masses of white floceulence on leaves of Quercus spp. 

quercicola Baker 



A SYNOPSIS OF THE APBIDIDAE 13 

— Alate viviparous females common. Venation normal, the third discoidal being 

twice-branched. Not on Quercv^ spp 2 

2. Antennae short, stout, with oval transverse sensoria (fig. 13). Forming galls 
on Arctostaphylos spp. (and Arhutus spp.) _ coweni (Ckll.) 

— Antennae longer and narrower with circular sensoria (figs. 9, 14—17). Living 

under thick masses of white flocculence on Fagus spp fagl (Linn.) 



1. Phyllaphis coweni (Ckll.) 

Figure 13 
Coekerell, Can. Ent., vol. 37, pp. 391-392. 1905. Pemphigus (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 4, pp. .559, 1911. Cryptosiphum tahoense 

n.sp. (desc). 
Davidson, Jour. Econ. Ent, vol. 5, p. 404, 1912 (list). 
Essig, Pom. Jour. Ent. Zool., vol. 7, pp. 187-195, 1915 (desc). 
- Records. — Arctostaphylos manzanita ; Oakville, Napa County, February, 1913 
(E. L. Brannigan) ; Mount Diablo, Contra Costa County (Davidson) ; Jasper 
Eidge, Santa Clara County, October, 1914 (B. A. Cornwell) ; Pine Hills, San Diego 
County, June, 1916.* A. pumella, A. tomentosa, Lake Tahoe, August, 1911 
(Davidson) : A. glauca, Alpine, San Diego County, June, 1916. 

This species is found more or less abundantly throughout the state 
wherever its host plants occur. Essig (1915) states it is found 
throughout the Kocky, Sierra Nevada, and Coast Range mountains, 
being more abundant in the central and northern parts of the state. 
The author has found it to be extremely abundant in the Cuyamaca 
and Laguna mountains in the extreme southern part of the state. 
The insects can be found at any time of the year in the galls on 
manzanita although most abundantly in the early fall. Collections 
by the author in June showed that the stem mothers and young vir- 
gogeniae only were present. A few weeks later the alate females were 
abundant, while in August the sexuales begin to appear. However, 
the alate viviparous females have been found in October and in 
Februaiy. This species forms galls on the leaves, and flower and 
fruit stalks of its host. Usually there is but one gall to a leaf, 
although sometimes four or five may be found. When first formed 
these galls are concolorous with the leaves; but as they become older 
they turn more and more reddish in color, until when mature they are 
a very bright red. 

2. Phyllaphis fagi (Linn.) 

Figures 9 to 12 
Linnaeus, Syst. Nat., vol. 2, p. 735, 1735. Aphis (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910 (list). 
Records. — Fagus sp., Palo Alto, 1910 (Davidson) ; Fagus sylvatica, Stanford 
University, April to May, 1915. 



* Records in which no collector 's name is mentioned refer to collections made 
by the author. 



1-i MISCELLANEOUS STUDIES 

This species has been taken only in the vicinity of Stanford Uni- 
versity, where it infests copper beach {Fagus stjlvatica). It may be 
easily recognized by the masses of whitish flocculence on the under 
side of the leaves. Each mass contains one individual, which is 
entirely hidden by it. In looking up the literature of this species 
the author found that there has been no description of it published in 
America, so below is included a brief description of specimens taken 
near Stanford University on April 28 and May 29, 1915. 

Alate viviparous female. — Prevailing color dark green, covered 
with a whitish flocculence. Tliis flocculence consists of wax threads 
as much as 3 mm. long. Head dusk.y, with frontal margin black. 
Eyes red. Antennae dusky, except II and basal one-third of III, 
which are pale. Beak pale with apex and joints dusky. Thorax 
dusky green with lobes black. Abdomen dark green with a row of 
black spots on each margin and abovit seven black transverse dorsal 
bands. Cornicles black. Cauda and anal plate concolorous with 
abdomen with distal margins slightly darker. First and second femora 
pale with apices only dusky ; third femora dusky throughout. First 
tibiae pale with apex dusky; second and thii'd dusky tlinnigliout. 
Tarsi black. Wings hyaline, stigma gray. 

Head twice as wide as long, furnished with many small wax 
glands. Antennae reaching to the cornicles or to the base of the 
Cauda, set on small tubercles (fig. 12). Ill is the longest segment, 
followed by IV, V, and VI. VI spur is merely a thumb-like projec- 
tion (fig. 16). The usual primary and accessory sensoria are present 
on V and VI. Secondary sensoria are found only on III (fig. 9). 
These are fairly large, almost circular, and placed in a single row 
along the segment. They number from four to seven, five being the 
average. The beak is short, reaching but slightly beyond the first 
coxae. The wings are normal, with a twice-branched third diseoidal. 
The cornicles are merely small pores. The cauda is short and knobbed, 
the anal plate emarginate or bilobed (fig. 11). 

Measurements: Body length 2.0 to 2.4 mm., width 0.8 to 1.04 mm., 
antennae total 1.55 to 2.06 mm., Ill 0.591 to 0.77 mm., IV 0.34 to 0.47 
mm., V 0.27 to 0.39 mm., VI 0.19 to 0.25 mm., cornicles (diameter) 
0.05 mm. 

Apterous viviparous female. — Prevailing color under flocculence 
pale yellowish green. Light brown markings as follows : two rows 
of four spots each across the prothorax, one large spot on each margin 
and one on tlie dorsum of the thorax, four spots on each abdominal 



A SYNOPSIS OF THE APHWIDAE IH 

segment, two doi"sal and two marginal. Antennae pale except VI, 
apical two-thirds of V, and apical one-third of IV. Legs pale with 
light brown spots at joints; tarsi black. Cauda small and conicle, 
cornicles not evident. 

Measurements: Bodj' length 2.9 to 3.0 mm., width 0.96 to 1.2 mm., 
antennae total 1.26 mm., Ill 0.36 mm., IV 0.32 mm., V O.204 mm., 
VI 0.205 mm. 

3. Phyllaphis quercicola Baker 

Figures 14 to 20 

Clarke, Can. Ent., vol. 35, p. 248, 1903. Schizoneura querci (Fitch) (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. S. querci (Fiteh) (list). 
Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. S. querci (Fiteh) (list). 
Davis, Ent. News, vol. 22, p. 241, 1911. Phyllaphis querci (Fitch) (biblig.) 
Davidson, Jour. Econ. Ent., vol. 7, p. 127, 1914. P. querci (Fiteh) (note). 
Gillette, Ent. News, vol. 25, p. 274, 1914. Phyllaphis sp. (list). 
Baker, Ent. News, vol. 27, p. 362, 191(!. P. quercicola n.n. for P. querci 
(Fitch) of Davis. 

Records. — Quercus agrifolia; Placer, Contra Costa, Santa Clara counties 
(Davidson, Clarke); Stanford University, April, 1915; Berkeley, September, 1915; 
Wynola, San Diego County, June, 1916; Charter Oak, Los Angeles County, Novem- 
ber, 1916. Quercus lobata, Stanford University (Davidson) ; Q. wisligenii, Placer 
County (Davidson) ; Q. dutnosa, San Diego, August, 1915; Quercus sp., Spreckels, 
Monterey County, 1913 (Gillette). 

This is a very common species of woolly aphis on the oaks, par- 
ticularly the live oak, through southern and central California. 
According to Davidson (1914) the stem mothers occur in pseudogalls 
on the edges of the leaves. The second generation lice, when mature, 
leave these galls to live on the upper and lower surfaces of the leaves, 
unprotected except for their woolly covering. The sexes, apterous 
oviparous females and alate males, occur late in the fall. The vivi- 
parous generations are all apterous. The writer has observed the 
stem mothers as late as August in San Diego County, while he has 
found the viviparous females on the under side of the leaves as early 
as mid-June in Berkeley. 

The identity of this species has never been definitely established. 
It was thought to be the species described by Fiteh (Kept. In.s. N. Y., 
vol. 5, p. 804, 1859) as Eriusomu querci, but in 1916 Baker pointed 
out the identity of Eriosania querci Fitch, proving it to be identical 
with a species of Anoecia found on Cornus and formerly considered 
to be A. corni Fab. Baker's decision is that the Quercus-Cornus 
species of the eastern United States is Anoecia querci (Fiteh) and 



16 MISCELLANEOUS STUDIES 

is distinct from our western one. In 1911 Davis described a species 
of woolly aphis from oak under the name of Phyllaphis querci (Pitch) 
stating that it is the same one as listed by Davidson. Baker proposes 
the name Phyllaphis quercicola for this species described by Davis. 
Consequently it is so listed in this paper. This species is not a typical 
Phyllaphis, but it fits that genus better than any other so is placed 
there provisionally. The figures (14-20) are from a specimen of alate 
male in the Davidson collection in Stanford University. 



Tribe Callipterini Wilson 

Wilson, Can. Ent., vol. 42, p. 2.53, 1910. 

The genera included in this tribe differ somewhat as considered by 
various entomologists. Since Wilson has worked out the synonomy 
of the various genera very well he is followed in preference to some 
of the European authors, although there ai'e some points in which 
he is mistaken. For instance, he places Ptcrooallis Passerini, Callip- 
teroides Mordwilko, Tuberculatus Mordwilko, SuhcalUpterus Mord- 
wilko, and Therioaphis Walker as synonyms of Myzocallis Passerini. 
In regard to this, he states, "In 1894 Mordwilko used A. coryli Goetze 
as the type of his genus Calliptcroides, but as this species..." He 
is mistaken in this, for in the paper referred to, Mordwilko used 
A. coryli Goetze as the type of the genus Myzocallis Passerini, and in 
1908 he gave as the type of Callipteroides, Callipterus nigritarsus 
He.yden {hetulae Koch). If nigritarsus Heyden is a synonym of 
bctulae Koch, as Mordwilko indicates, then Calliptcroides is a synonym 
of Euceraphis Walker, for C. hetulae Koch certainly falls into this 
genus, as described by Wilson himself. The key to the California 
genera below is adapted from Wilson's key (Can. Ent., vol. 42, pp. 
253-254, 1910). 

• Key to Californi.v Genera of Callipterini 

1. Antennal tubercles prominent (fig. 21) ; antennae always exceedingly long.... 2 

— Antennal tubercles wanting or very small (fig. 22) ; antennae variable, some- 

times shorter than the body 3 

2. Cornicles very long and large (figs. 23-24) 4 

— Cornicles very short and more or less constricted in the middle 5 

— • Cornicles little more than pores (fig. 25). Wings held horizontal at rest. 

Monellla Oestlund 

3. Cornicles distinct, usually being longer than broad in the middle (fig. 26) 6 

— Cornicles little more than pores, and broader than long (fig. 25). Wings 

held horizontal at rest MonelUa Oestlund 



.4 SYNOPSIS OF THE APBIBIDAE 17 

4. Cornicles one-fourth the length of the body or more, swollen in the middle 

(fig. 24) Drepanosiphum Koch 

— ■ Cornicles large and nearly one-fourth the length of the body, swollen at the 
base and tapering toward the middle (fig. 23) ....Drepanaphls Del Guercio 

5. Inner side of antennal tubercles about one-half the length of the inner side 

of the first antennal joint (fig. 29) Euceraphis Walker 

— Inner side of antennal tubercles more than one-half the length of the inner 

side of the first antennal segment (figs. 27-28) Calaphis Walsh 

6. Antennae longer than body, except in CalUpterinella, with VI spur not much 

shorter than VI base (fig. 31) 7 

— • Antennae shorter than the body, with VI spur very short, often being little 
more than a nail-like process (fig. 34) 9 

7. VI spur considerably longer than VI base, being one and one-half to two 

times as long. Anal plate emarginate but not deeply bilobed. 

Callipteiinella Van der Goot 

— VI spur about equal to or shorter than VI base. Anal plate deeply bilobed 8 

8. VI spur and VI base subequal (fig. 31). Cornicles t^vice as long as broad 

in the middle and constricted in the middle (figs. 26, 32). 

Myzocallis Passerini 

— VI spur shorter than VI base (fig. 30). Cornicles much broadened at base 

(fig. 33) Eucallipterus Schouteden 

9. VI spur less than one-half the length of VI base (fig. 34). Cornicles not 

longer than broad at the base, and constricted in the middle (fig. 35). 

Chromaphis Walker 

— VI spur at least one-half as long at VI base (figs. 63, 66). Cornicles short, 

about as long as broad and placed on a broad base CaUipterus Koch 



2. Genus Drepanosiphum Koch 
Koch, Die Pflanzenlause, p. 201, 1855. Type Aphis palantanoides Sehrank. 
4. Drepanosiphum platanoides (Sehrank) 

Figures 21, 24, 36 

Sehrank, Fauna Boic, vol. 2, p. 1206, 1801. Aphis (orig. desc). 
Wilson, Jour. Econ. Ent., vol. 2, p. 349, 1909 (desc. ala. vivi., ala. ovi. 

females). 
Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 759, 1912 (list). 

Becords. — Acer macrophyJlum, A. nerjundo; Berkeley, 1915 (Essig) ; Stan- 
ford University, October, 1914, April, 1915; A. pseudoplatanus, Stanford Univer- 
sity, November, 1914 (Morrison); A. sacdharum, Berkeley, June, 1915; Platanus 
racemosus. Stanford University (Davidson) ; Acer sp., San Lorenzo, 1908 (Wil- 
son). 

This is a very common species in the San Francisco Bay region 
on various species of maples, and on box elder and western sycamore. 
In April the alate and apterous viviparous females are abundant, 
remaining' so throughout the summer and early fall. In tlie later 
fall (October and November) the sexes appear. Just where the eggs 



18 MISCELLANEOVS STUDIES 

are laid the author is unable to say. A curious fact is that the 
oviparous females are alate as well as apterous. The author has never 
seen the alate forms, but Wilson (1908) describes them. 

:l. Genus Drepanaphis Del Cxuerein 

Del Guereio, Eivista di patologia vegetable, vol. 4, pp. 49-.53, 1909. Type 
Siplwnophora accrifolii Thomas. 

5. Drepanaphis acerifolii (Thomas) 

Figures 23, 37 

Thomas, Illinois Lab. Nat. Hist., Bull. 2, p. 4, 1878. Siphonophora (orig. 

desc.). 
Clarke, Can. Ent., vol. 35, p. 249, 1903. Drepanosiphum (list). 
Sanborn, Kan. Univ. Sci., Bull. 3, p. 45, 1904. Drepanosiphum (desc. ala.). 
Davidson, Jour. Econ. Ent., vol. 2, p. 303, 1909. ' Drepmwsiphum (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910. Macrosiphum (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 760, 1912 (list). 
Essig, Mon. Bull., Cal. Comm. Hort., vol. 3, p. 85, 1914 (list). 
Essig, Mon. Bull., Cal. Comm. Hort., vol. 3, p. 445, 1914 (list). 

Records. — Acer sp. : Stanford University (Davidson); Sacramento (Essig); 
Hanford, Fresno County (B. V. Sharp) ; A. macrophyUum, A. saccharinum. Berke- 
ley, July to October, 1915; Eiverside, October, 1916; A. dasijcarpam, A. plat- 
anoides, Berkeley, 1915 (Essig); Quercu-s .sp. (live oak), Berkeley (Clarke) (?). 

Tliis is as common a species on maple in the San Francisco Bay 
region as the preceding one. It has also been taken in the Sacramento 
and the San Joaquin valleys, and in southern California. It is a 
species easily recognized by its dark markings and the dorsal tubercles 
on the first and second abdominal segments. 

4. Genus Calaphis AValsh 
Figure 28 
Walsh, Proc. Ent. Soc. Phila., vol. 1, p. 301, 1863. Type C. hetulclla ii.sp. 

(). Calaphis betulaecolens (Fitch) 

Figures 27-:'.S 

Fitch, Cat. Honiop. N. Y., p. 66, 1851. Aphis (orig. desc). 

Clarke, Can. Ent., vol. 35, p. 249, 1903. CalUpterus (list). 

Davidson, Jour. Econ. Ent., vol. 2, p. 301, 1909. Callipteru.^ (list). 

Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. CalUpterus (list). 

Essig, Pom. Jour. Ent., vol. 3, p. 556, 1911 (syn.). 

Davidson, Jour. Econ. Ent., vol. 5, p. 404, 1912 (desc. sexes). 

Essig, Pom. Jour. Ent., vol. 4, p. 760, 1912 (list). 

Essig, Mon. Bull., Cal. Comm. Hort., vol. 3, p. 445, 1914 (list). 

Baker, Proc. Ent. Soc, Washington, vol. 18, p. 186, 1916 (desc). 

Records. — Betula sp., Alameda, Contra Costa, Santa Clara counties (Clarke, 
Davidson, Essig, Morrison, and the author). 



A SYNOPSIS Of THE APHIDIDAE 19 

This is a common species of aphid on birch (Betula spp.) in the 
San Francisco Baj- region. In the early part of March the eggs begin 
to liatch. In 1915 at Stanford Universitj- eggs began to hatch on 
March 8, the process coiitimiing for several days. A month later 
both alate and apterous females were quite abundant ; the alate 
females being undoubtedly the stem mothers, the apterae belonging 
to the second generation. Viviparous generations appeared through- 
out the summer. During August the sexes, alate males and apterous 
oviparous females, occurred. In 1914 the sexes and sexupara \v(^ro 
noticed on August 28. Egg laying occurred shortly afterward, the 
eggs being laid in the crotches of the twigs and under the curled 
edges of the bark. Birch is the only recorded host plant. 



5. Genus Euceraphis "Walker 

Walker, The Zoologist, p. 2001, 1870. Type Aphis hetulac Koch. 

Key to Californi.\ Species 

1. Body light green; third joint of antennae with about 13-18 sensoria on basal 

one-half (fig. 39) giUettei Dvdn. 

— Body yellow with dark markings on head and thorax, and often with as 
many as eight black transverse stripes on the abdomen (the number varies 
between none and eight) ; third antennal segment with 19-25 sensoria 
(fig. 40) betulae (Koeh) 



7. Euceraphis betulae (Koch) 

Figures 29, 40 

Koch, Die Pflanzenliiuse, p. 217, 1855. Callipterus (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 5, p. 405, 1913 (dese. ovi. female). 
Davidson, Jour. Econ. Ent., vol. 7, p. 129, 1914 (desc. stem mother). 

Beeords. — Betula sp. : Oakland (Davidson); Palo Alto, March to April, 1915. 

David.son lists this species, describing the stem mother and 
oviparous female from the San 5'rancisco Bay region. The author 
found it in Palo Alto during March and April. 1915, on Betula alha. 
According to Davidson the stem mothers hatch from the eggs about 
the middle of February, feeding on the .stems until the leaves open in 
March. The viviparous generations occur during the summer. He 
took the oviparous females in November. His description of the stem 
mother gives three dusky traJisverse bands on the abdomen. The 
author has found this to be variable, the number ranging from none 
to eight. 



20 MISCELLANEOUS STUDIES 

8. Euceraphis gillettei Davidson 

Figure 39 

Clarke, Can. Ent., vol. 35, p. 248, 1903. Lachmi^ alnifoliae Fitch (list). 
Davidson, Jour. Econ. Ent., vol. 2, p. 300, 1909. L. alnifoliae Fitch (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 375, 1910. L. alnifoliae Fitch (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912. Lachn-us alnifoliae Fitch 

(list). 
Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912. Lalinus alnifoliae Fiteh (note). 
Davidson, Jour. Econ. Ent., vol. 8, p. 421, 1915 (orig. desc). 

Secords. — AhiTis rhombifolia; Berkeley (Clarke), Stanford University, San 
Jose, Walnut Creek (Davidson), Stanford University, March, 1915. 

This species was reported from alder by Clarke and Davidson as 
Lachnus alnifoliae Fitch. Essig, in his Host plant list of California 
Aphididae, lists Callipterus alnifoliae (Fitch) on Alnus rhombifolia, 
but later states that this citation should be Lachnus alnifoliae Fitch. 
Therefore he referred to this new species of Davidson. The author 
took both apterous and alate viviparous females of this species on 
Alnus rhombifolia, along the banks of the San Franeisquito Creek, 
near Stanford University, on March 19, 1915. During the spring it 
was quite common there. 

6. Genus Eucallipterus Sehouteden 
Schouteden, Mem. Soc. Ent. Belg., vol. 12, 1906. Type Aphis tiliae Linn. 
Key to California Species 

1. Wings hyaline; III pale except at the apex, with 5-7 sensoria on the basal 

one-fifth (fig. 41) flava (Dvdn.) 

2. Wings vpith veins clouded; III with apical one-fifth and basal one-half dusky, 

and with about 13-15 sensoria on the basal one-half (fig. 42). 

tiliae (Linn.) 



9. Eucallipterus flava (Davidson) 

Figure 41 

Davidson, Jour. Econ. Ent., vol. 5, p. 406, 1912. Euceraphis (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 8, p. 423, 1915 (desc. sexes). 

Eecords. — Alnus rhoml}ifoli<i ; San Jose, Walnut Creek (Davidson), Stanford 
University (Morrison). 

This is an uncommon species in the San Francisco Bay region on 
Alnus rhonihifolia, occurring on the under side of the leaves. The 
author has never collected it, but has specimens from Davidson, taken 



A SYNOPSIS OF THE APHIDIDAE 21 

in April, 1913, near Walnut Creek, Contra Costa County. According 
to Davidson the sexes appear in October, egg laying occurring diiring 
the first part of November. The eggs are laid at the axils of the new 
buds and on the twigs or canes. These hatch the following spring, the 
stem mothers being found in the early part of April. 



10. Eucallipterus tiliae (Linn.) 

Figures 7, 30, 33, 42, 50 

Linnaeus, Syst. Nat., vol. 2, p. 734, 173.5. Ajihis (orig. desc). 
Davis, Ann. Ent. Soc. Amer., vol. 2, p. 33, 1909. Callipterus (desc, biblic). 
Davidson, Jour. Ecou. Ent., vol. 2, p. 302, 1909. Callipterus (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. Callipterus (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 370, 1910. Calliptenis (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 763, 1912 (list). 

Becords. — Tilia amerieana, Tilia europea: Stanford University (Davidson), 
Berkeley, August, 1914 (Es.sig) ; Stanford University, April to May, 1915; Berke- 
ley, June, 1915. 

In the San Francisco Bay region this very pretty aphid is quite 
common on basswood or linden. The author has taken it throughout 
April, MaJ^ and June. Essig found it abundantly in August. It is 
very easily recognized when found at rest on the under side of the 
leaves of its host bj- the two black lines extending from the front of 
the head along the margins of the thorax and joining with the costal 
margins of the wings. It so appears that these lines are continuous 
from the front to the tip of the wings. 



7. Genus Myzocallis Passerini 
Passerini, Gli Afidi, p. 28, 1860. Type Aphis coryli Goetze. 
Key to C.\liforni.\ Species 

1. Wings hyaline 6 

— Wings not h.valine, with portions shaded (fig. 262) 2 

2. Costal cell of wings hyaline (figs. 266, 267) 3 

— Costal cell of forewings dusky or shaded (figs. 263, 264) 5 

3. First discoidal vein dusky, otherwise the wing is hyaline. VI with spur shorter 

than base. Apical one-half of III dusky (fig. 47). Cornicles pale. Found 
on Alnu-s spp alnifoliae (Fitch) 

— Wings not as above (figs. 266, 267). VI with spur either equal to or longer 

than base. Ill with less than apical one-half dusky 4 

4. Cornicles pale. Abdomen without dusky dorsal markings. On Quercus spp. 

mauieri Swain 

— Cornicles dusky (fig. 62). Abdomen with dusky dorsal markings. On Casta- 

nea spp. and Quercus spp davidsonl Swain 



22 MISCELLANEOUS STUDIES 

5. Cornicles pale. Wings with greater portion cloudy (fig. 262). Antennae with 

only tips of III to VI dusky. On Qiiercm spp discolor (Monell) 

— Cornicles pale with apex dusky. Wings with dusky band along costal margin 

(fig. 263). Antennae with tips of III and IV, apical one-half of V, and 
all of VI and spur dusky. On Quercus spp bellus (Walsh) 

6. Abdomen with four spine-like tubercles on the dorsum of the first segment. 

VI with base and spur subequal, III being considerably longer than both. 
Cornicles pale, small, and inconspicuous. On Ultmts spp. 

ulmifolii (Monell) 

— Abdomen without tubercles as above 7 

7. Ill shorter than VI (base and spur). On Q-uercus spp punctatus (Monell) 

— Ill not shorter than VI (base and spur) 8 

8. VI with spur about twice as long as base (fig. 44). Cornicles pale. On 

Cori/lm spp coryli (Goetze) 

— ■ VI with spur at most only slightly longer than base 9 

9. Ill with apex only dusky (figs. 57, 58). Cauda pale 10 

— Ill dusky throughout (fig. 268) or with apex and a band near the base dusky 

(fig. 48). Cauda dusky 11 

10. Cornicles pale. Antennae longer than body. Sensoria on III (two or three 

in number) small and located close to the base of the segment (fig. 57). On 
Pasmiia spp pasaniae Dvdn. 

— Cornicles dusky, at least apical one-half. Antennae not longer than the body. 

Sensoria on III (five or more in number) fairly large and on basal two- 
thirds of segment (fig. 58). On Quercus spp quercus (Kalt.) 

11. Abdomen with dusky dorsal markings. Ill dusky throughout (fig. 268). Ou 

Arundo spp arundinariae Essig 

— Abdomen without dusky dorsal markings. Ill with apex and band near base 

dusky (fig. 48). On Arutido s-pp arundlcolens (Clarke) 

11. Myzocallis alnifoliae (Pitch) 

Figure 47 
Fitch, Cat. Homop. N. Y., p. 67, 1851. Lachnus (orig. desc). 
Essig, Pom. Jour. Ent., vol. 4, p. 764 (762), 1912. M. nJni (Fabr.) (desc. 

viviparae ) . 
Baker, Jour. Eeon. Ent., vol. 10, p. 421, 1917 (note). 
Eecords. — Alnus rhombifolin ; Santa Paula (Essig). 

Only once has this species been taken in California, by Essig in 
August, 1911, near Santa Paula, Ventura County. At that time it 
was very abundant on the under side of tlie leaves, causing a large 
amount of sooty mold. 

12. Myzocallis arundlcolens f Clarke) 
■ Figures 22, 48, 51, 52 
Clarke, Can. Ent., vol. 35, p. 249, 1903. Calliptenis (orig. desc). 
Davidson, Jour. Eeon. Ent., vol. 2, p. 301, 1909. Callipterus (list). 
Davidson, Jour. Eeon. Ent., vol. 3, p. 376, 1910. Callipterus (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912 (list, in part). 
Essig, Univ. Calif. Publ. Entom., vol. 1, p. 305, 1917 (desc.). 



J SYNOPSIS OF THE APHWIDAE 23 

Records. — Bamboo, Berkeley (Clarke, Essig) ; Arundinaria japonica, Berkeley, 
June, 1915. 

In the San Francisco Bay region and in the Sacramento Valley 
this species is often found infesting the upper and lower surfaces of 
the leaves of various bamboos, particularl}' species of ArundUiaria, 
Bamhitsa, and rhijUostachys, and the giant reed {Arundo donax). 
Reports list it from Alameda, Sacramento, San Francisco, and Santa 
Clara counties. The species described by Davidson (1914) as Eiwal- 
liptcrus arundicolens (Clarke) and reported from southern California 
by Essig (1912) proves to be distinct, and was described by Essig 
(1917) as M. arimdinarme. The following brief description is from 
a collection made by the author on June 9, 1915, from Arundinaria 
japonica on the campus of the Universitj' of California in Berkeley. 

Alate viviparous female. — (Second generation?) Prevailing 
color, pale yellow. Head twice as wide as long, pale yellow, with 
prominent red eyes. Antennal tubercles absent. Antennae longer 
than liody; formula III, IV, V, VI spur, VI base, I, II. Segments all 
pale except tlie margins of I and II, the apices of III, IV, V, and a 
band about one-sixth tlie length of III a short distance from the base 
of III (fig. 48), which are black, and VI which is slightlj-- dusky. 
There are five or six transverse secondaiy sensoria on III, located in 
the dark band. The usual primary sensoria are present on V and VI, 
and the usual accessor sensoria on VI. Beak pale and short, reaching 
on\\ to the middle of the fii-st coxae. Thorax and abdomen normal, 
pale yellow, without tubercles or dusky markings. Cornicles (fig. 51) 
pale, short, broader at base than at apex. Cauda short, constricted 
in the middle, with distal end black. Anal plate (fig. 52) pale, deeply 
bilobed. Wings normal, hyaline, with the first and second discoidal 
veins and the base of the stigmal vein darker than the others. There 
is a perceptible shading at the tip of each vein. 

Measurements: Body length 1..326 to 2.023 mm. (av. 1.644 mm.), 
width of thorax 0.51 to 0.68 mm. (av. 0.612 mm.), antennae total 
2.839 to 3.077 mm. (av. 2.9299 mm.). Ill 0.8925 to 0.986 mm. (av. 
0.9324 mm.), IV 0..578 to 0.663 mm. (av. 0.6423 mm.), V 0.527 to 
0.561 mm. (av. 0.5403 mm.), VI base 0.306 to 0.323 mm. (av. 0.3103 
mm.), VI spur 0.34 to 0.425 mm. (av. 0.3691 mm.), cornicle 0.595 to 
0.765 mm. (av. 0.7002 mm.), cauda 0.153 mm., wing length 2.25 to 
3.96 mm. (av. 2.9097 mm.), width 1.02 to 1.122 mm. (av. 1.071 mm.), 
expansion 6.341 to 6.97 mm. (av. 6.6555 mm.). 



24 MISCELLANEOUS STUDIES 



13. Myzocallis arundinariae Essig 

Figure 268 

Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912. M. arundicolcns (Clarke) (in 

part). 
Davidson, Jour. Econ. Ent., vol. 7, p. 129, 1914. EucaUipterus arundi- 

colens (Clarke) (desc. viviparae). 
Essig, Univ. Calif. Publ. Entom., vol. 1, pp. 302-305, 1917 (orig. desc). 

Records. — Arundo sp., San Francisco Bay region (Davidson) ; Arundinaria 
japonica, Santa Barbara (Essig) ; Eiverside, January to May, 1917; Ai-undo 
donax, San Diego, April to June, 1916. 

This is the commonest bamboo-infesting species in southern Cali- 
fornia and parts of central California. For some time it was con- 
sidered as M. arundicolcns (Clarke) but this past j-ear Essig pointed 
out the differences, describing it as a new species. 

14. Myzocallis bellus (Walsh) 

Figures 45, 46 

Walsh, Proc. Ent. Soe. Phila., vol. 1, p. 299, 1862. Aphis (orig. desc). 
Essig, Pom. Jour. Ent. Zool., vol. 7, pp. 195-200, 1915. Callipierus (desc). 

Records. — Quercus agrifolia, Alhambra, Los Angeles County (Essig) ; Ventura 
(Essig). 

Two collections have been made of this species in California, both 
in soutliem California, in January, 1912, in Alhambra, and in May, 
1913, in Ventura. Both of these consisted only of the alate females 
(stem mothers), and were described by Essig. 



1.5. Myzocallis davidsoni Swain 

Figures 60, 61, 62, 267 

Clarke, Can. Ent., vol. 35, p. 249, 1903. Callipierus castaneac Fitch (list). 

Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Callipterus castaneae 
(BuCkton) (list). 

Davidson, Jour. Econ. Ent., vol. 5, p. 405, 1912. CaJaphis castaneae (Buck- 
ton) (desc sexuales). 

Essig, Pom. Jour. Ent., vol. 4, p. 760, 1912. Calaphis castaneae (Fitch) 
(list). 

Swain, Trans. Am. Ent. Soc, vol. 44, p. 1, 1918 (orig. desc). 

Records. — Castanea sp., Berkeley (Clarke, Essig, Swain), Stanford University 
(Davidson, Swain), San Jose (Davidson) ; Quercus pedunculata, Berkeley (Swain, 
Essig). 

This species was first reported in California by Clarke as CaUip- 
terus castaneae Fitch and later by Davidson as Callipterus castaneae 



A SYNOPSIS OF THE APHIDIDAE 25 

Buckton. Kecently the author di'.scrihed the species from specimens 
taken in Berkek'y on chestnut and oak. It cannot be the Callipterus 
castaniac of Fitch, beeausc the hitter is really a Calaphis. It ma.y be 
the same species that Buckton had when describinfi: his Callipterus 
castaneae, in which case his name would be dropped as Fitch's species 
has priority, and is replaced by the author's name, M. davidsoni. It 
is more or less common throughout tlie San Francisco Bay region on 
chestnuts, and in one case on two specimens of Qucrcus pcdunculata 
in Berkeley. The stem mothers appear during the late spring, in 
April and May. Viviparous generations are produced throughout the 
summer, the sexuales occurring in October and November. 



16. Myzocallis coryli (Goetze) 

Figures 43, 44, 53, 54 

Goetze, Ent. Beitrage, vol. 2, p. 311, 1778. Aphis (orig desc). 
Qarke, Can. Ent., vol. 35, p. 249, 1903. Callipterus (list). 
Davis, Jour. Econ. Ent., vol. 3, p. 417, 1910. Callipterus (desc). 
Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912 (list). 

Becords. — Coryln-s sp., Berkeley (Clarke) ; Cori/lus rostrata, San Francisco Bay 
region (Davidson) ; C. rostrata var. calif arnica, C. maxima, Berkeley, August, 
1914, June to July, 1915. 

In the San Francisco Bay region this species is quite common on 
alder. During the seasons of 1914 and 1915 tlie author observed it 
to be very abundant on species of alder on the University of California 
campus. He has never found it in the south, however. 



17. Myzocallis discolor (IMoncll) 

Figures 262, 263 

Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 30, 1879. Callipterus (orig. 

dese. ) . 
Williams, Univ. Neb. Studies, vol. 10, p. 115, 1910. Callipterus (desc). 

Record. — Quercus macrocarpa, Sacramento, October, 1916 (Davidson). 

The author received specimens of this species from Davidson, 
which were found in October, 1916, on Quercus macrocarpa in Sacra- 
mento. The determination was made by Davis. Below are a few 
descriptive notes to supplement Williams' description listed above. 

Alate viviparovs female. — Antennae about as long as body, III 
the longest segment, followed by IV, VI, and V. VI spur is slightly 
longer than the base. The antennae are rather slender as compared 



26 MISCELLANEOUS STUDIES 

with other species of this genus. Primary sensoria are present on 
V and VI as usual, and accessory sensoria on VI. Tliere are about 
seven secondary sensoria on III (fig. 262), which are more or less oval 
to circular, and located on the basal two-thirds of the segment. The 
cornicles, cauda, and anal plate are typical of the genus. 

Measurements: Body length 1.28 to 1.37 mm., antenna total 1.41 
mm.. Ill 0.459 mm., IV 0.306 mm., V 0.264 mm., VI 0.289 mm. (base 
0.119 mm., spur 0.17 mm.), cornicles 0.68 mm., wing length 2.074 to 
2.414 mm., width 0.68 to 0.833 mm. The two dusky transverse bands 
across tlie fore wings (fig. 263) constitute the most distinguishing 
character. The branching of the third discoidal is quite variable. 

18. Myzocallis punctatus (ilonell) 

Monell, U. S. Gk-ol. Geog. Surv., Bull. 5, p. 31, 1879. Callipterus (orig. 

desc). 
Clarke, Can. Ent., vol. .35, p. 249, 1903. Callipterus hyalinus Monell (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912. M. hyalimts (Monell) (list). 
Eeoord. — Quercus imbricata, Berkeley (Clarke). 

This is a doubtful species, reported only bj' Clarke from Quercvs 
imhricata in BerkeleJ^ It is the author's opinion that this is the same 
species listed by Davidson as M. quercus (Kalt.). 

10. Myzocallis maureri Swain 

Figures 55, 56, 266 

Swain, Trans. Am. Ent. Soc., vol. 44, p. 4, 1918 (orig. desc). 

Records. — Quercus agrifolia, Berkeley (Swain) ; Quercus kelloggii, Julian, San 
Diego County (Swain). 

This species has been taken in Berkeley and in the Cuj'amaca 
Mountains of San Diego County by the author. Essig has also taken 
it in Berkeley. It is never abundant, but the author has observed it 
several times and in several places in the localities mentioned. 

20. Myzocallis pasaniae Dvdu. 

Figure 57 

Davidson, Jour. Econ. Ent., vol. 8, p. 424, 1915 (orig. desc). 

Secords. — Pasania densiflora, Stevens Creek Canyon, Santa Clara County 
(Davidson), Berkeley, February, 1915 (Essig). 

This is a species found occasionally on tanbark oak in the San 
Francisco Bay region. The author has never taken it but has speci- 
mens from Davidson and Essig. 



A SYNOPSIS OF THE APHIDIDAE 27 

21. Myzocallis quercus (Kalt.) 

Figures 31, 32, 58 

Kaltcnbach, Monog. d. Pflanzenlause, p. 98, 1843. Aphis (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909. Callipterus (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Callipterus (list). 
Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911. Callipterus (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912 (list). 
Davidson, Jour. Econ. Ent., vol. 7, p. 130, 1914 (desc). 

Records. — Querais agrifolia; Stanford University, San Jose, Penryn, Placer 
County (Davidson) ; Q. lobata, Santa Clara County (Davidson) ; Berkeley, 1915 
(Essig); Q. pedunculata, Berkeley, August, 1914; Q. douglasii, Stanford Univer- 
sity, November, 1910, April, 1911 (Morrison); Q. rohur, Oakland (Davidson). 

This is a variable species more or less eominon in the Sau Fran- 
cisco Bay region and in the Sacramento Valley on various species of 
oaks. When he first reported it Davidson was doubtful of its identitj'. 
Later, however, it was identified by Peter Van der Goot^ as this 
species. 

22. Myzocallis iilmifolii (Monell) 

Figure 59 

Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 29, 1879. Callipterv.9 (orig. 

desc). 
Davidson,' Jour. Eeon. Ent., vol. 2, p. 301, 1909. CaUiptenm (list). 
Davidson, Jour. Eeon. Ent., vol. 3, p. 376, 1910. CalUptcru.s (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912 (list). 

Hecords, — Vlmus sp., Stanford University (Davidson), Ulmus americana, Wal- 
nut Creek, October, 1913 (Davidson). 

Davidson reports this as common on elms in the San Francisco 
Bay region. However, the author has never collected it. The follow- 
ing brief descriptive notes are from an alate viviparous female, taken 
in Walnut Creek by Davidson. The most distinguishing character is 
the presence of a pair of small but prominent tubercles on the mid- 
dorsum of the first and second abdominal segments. The usual 
primarj^ and accessory sensoria are present on V and VI. Secondary 
sensoria (fig. 59) are present on the basal one-half to two-thirds of 
III. These are transversely linear or oval, and number about six. 
The cornicles are very short, being fully as broad at the apex as long. 
Cauda and anal plate normal. Wings normal, radial vein indistinct, 
first discoidal curving toward base of wing. Body length 1.836 mm., 
width of thorax 0.578 mm., antennae total 1.309 to 1.326 mm.. Ill 



5 In 1917 George Shinji (Ent. News, vol. 27, February, 1917) described three 
species, M. essiggi n.sp., M. woodworthi n.sp., and M. hyalinus (Monell), all of 
which are undoubtedly but varieties of this species, M. quercus (Kalt.). 



28 MISCELLANEOUS STUDIES 

0.442 mm.. IV 0.255 to 0.272 mm., Y 0.221 to 0.2465 mm., VI 0.255 mm. 
(base 0.136 mm., spur 0.119 mm.), cornicles height 0.034 mm., diam- 
eter at apex 0.034 mm., wing length 1.581 to 1.768 mm., width 0.663 
to 0.68 mm., expansion 3.825 mm. 

8. Genus Chromaphis "Walker 

Walkei-, The Zoologist, p. 2001. 1870. Type Lachiius juglandicoJa Kalt. 

23. Chromaphis juglandicola (Kalt.) 

Figures 34, 35 

Kaltenbach, Monog. d. Pflanzenlause, p. 151, 1843. Larhnus (oi'ig. desc). 
Essig, Pom. Jour. Ent., vol. 1, p. 51, 1909. Callipteras (desc. vivi.). 
Essig, Pom. Jour. Ent., vol. 4, p. 763, 1912 (list). 
Davidson, U. S. Dept. Agr., Bull. 100, pp. 2-19, 1914 (desc. all forms). 

Secords. — Juglans regia; San Francisco Bay region, southern California. 

This walnut aphis is the most abundant and injurious of the 
species attacking walnut in California. It is more or less abundant 
throughout the San Francisco Bay region, vvliile in southern Cali- 
fornia during certain seasons it is an important pest. Davidson 
(1914) has described all the forms and studied the life history care- 
fully, so but little comment is necessary. In 1915 tlu^ author 
observed the young stem mothers on March 22 in Sunnyvale, Santa 
Clara County. Three weeks later the second generation was well 
advanced. From tlie first of May on, in 1916, the viviparae were 
abundant on walnuts throughout San Diego County, from nursery 
stock in San Diego to a few cultivated trees at Santa Ysabel (altitude 
3000 feet). From the middle of October until well into December, 
1916, the sexuales were found throughout Los Angeles and Riverside 
counties. 

9. Genus Callipterus Koch 
Koch, Die Pflanzenlause, p. 208, 1855. Type Aphis juglandis Kalt. 

The two members of this genus in California have been considered 
heretofore as species of Moncllm Oestlund (genus 10), but according 
to Davis" they can not lie so considered for in Monellm the wings are 
laid flat on the abdomen when at rest. This is found only in Moncllia 
caryella (Fitch). Incidentally it may be remarked that the species 
known by that name in California does not have that habit, so 
should really be placed in this genus, Calli-ptems Koch. However, as 
it is identical with eastern specimens, except for this habit, the author 



6 Essig, E. O., Beneficial and Injurious Insects of California, Mon. Bull. Cal. 
Comm. Hort., vol. 4, p. 83, 1915. 



A SYNOPSIS OF THE AFHIDIDAE 29 

has tliought best to retain it in MoneUis, at least for the time being. 

Key to California Species 

1. VI spur about equal to or slightly longer than VI base. Tibiae mostly pale. 

caryae Monell 

— - VI spur shorter than VI base. Tibiae entirely dark. Considerably larger than 

preceding species calif omicus (Essig) 

2J:. Callipterus calif omicus (Essig) 
Figures 63, 64 

Essig, Pom. Jour. Ent., vol. 4, p. 767, 1912. Monellia (orig. desc). 
Davidson, U. S. Dept. Agr., Bull. 100, p. 34, 1914. MonelUa (list, key to 
walnut aphids). 
Seeords. — Juglanx coUfonUca (California black walnut); Santa Paula. 

In 1912 Essig described this species from .specimens taken near 
Santa Paula in July. 1911. No otlier definite collections are known 
to the writer, although Essig reports it as more or less abundant on 
the California black walnut throughout the southern part of the state. 
Davidson has not found it in the San Francisco Bay region, nor has 
the author ever observed it, either in the bay region or in southern 
California. 

25. Callipterus caryae IMonell 

Figures 65, 66 

Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 31, 1879 (orig. desc). 
Clarke, Can. Ent., vol. 35, p. 249, 1903 (list). 
Davidson, Jour. Econ. Ent., vol. 2, p. 301, 1909 (list). 
Davidson, Jour. Econ. Ent.,- vol. 3, p. 376, 1910 (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 764, 1912. Monellia (list). 
Davidson, U. S. Dept. Agr., Bull. 100, pp. 19-20, 1914. Monellia (desc. 
all forms). 

Seeords. — Juglans regia, J. calif ornica; Berkeley, Stanford University, San 
Jose, San Francisco Bay region. 

This species is more or less common in the San Francisco Bay 
region on walnuts. Davidson has described all the foi'ms and noted 
its life history. The author has not taken the species. 

10. Genus Monellia Ocsthnid 

Oestlund, Minn. Geol. Nat. Hist. Surv., Bull. 4, p. 44, 1887. Type Aphis 
caryella Fitch. 

This genus, as described by Oestlund, differs from CalUpterus par- 
ticularly in the position of the wings when the insects are at rest. In 
Callipterus they are held roof-like over the body as is usual in aphids. 
but ill Monellia they are laid flat on the abdomen. It includes but 
the one species, M. caryella (Fitch). 



30 



MISCELLANEOUS STUDIES 



26. Monellia caryella (Fitch) 

Figures 25, 67, 68 

Fiteh, Insects N. Y., vol. 1, p. 163, 1855. Aphis (orig. dese. apt. vivi.). 
Fitch, Ins. N. Y., vol. 3, p. 448, 1856. Callipterus (first dese. ala. vivi.). 
Davidson, Jour. Econ. Ent., vol. 7, p. 132, 1914 (list). 
Davidson, U. S. Dept. Agr., Bull. 100, pp. 26-34, 1914 (dese. all forms). 

Records. — Juglans calif ornica, J. Nigra, J. regia; San Jose, Walnut Creek 
(Davidson) ; Stanford University, May to June, 1915. 

A more or less common species on both the native black walnut, 
and the cultivated walnut in the San Francisco Bay region. This 
species, while very similar to the preceding species, is probably the 
more common of the two. The following- table of differences is taken 
from Davidson ■/ 



Form 
Alate viviparous female 



Callipicrus cari/ae Monell MonelUa caryella (Fitch) 

Antennal joint III very Antennal joint III quite 
slightly thickened bas- noticeably thickened 

ally. 

Sensoria 



on antennal 

joint III occupying 

basal half or two- 
thirds. 



for its basal half. 

Seu.soria on antennal 
joint III occupying 
basal third. 



Pupa of viviparous 

female 
Oviparous female 



Antennal joint VI and Antennal joint VI one- 
its spur or filament third as long again as 
subequal, or VI less its spur or filament, 
than spur. 

■ Dusky knee spots often Dusky knee spots absent, 
present. 

Four longitudinal rows Six longitudinal rows of 

of capitate spines. capitate spines. 

Smaller than viviparous Larger than viviparous 

female. female. 

Four longitudinal rows Six longitudinal rows of 

of cipitate spines. capitate spines. 



This species is distinct from the preceding and according to Mor- 
rison, who has examined eastern species, is structurally identical 
except in the matter of the wings. He writes as follows : 



'Davidson, W. M., Walnut aphides in California, IT. S. Dept. Agr., Bull. 100, 
p. 28, 1914. 



A SYNOPSIS OF THE APHIDIDAE 31 

I made a very careful study of specimens from California, sent me by David- 
son, and of specimens collected both in Indiana and New York (type locality). 
I was unable to find any structural differences that would definitely separate the 
two lots of specimens, with the exception of the position of the wings. These are 
laid flat when at rest in the eastern specimens, but are not so in the Californian 
specimens, according to Davidson. In spite of this apparent agreement, I feel 
that the two must be distinct. 

If this is the ease, that the wings are not laid flat at rest, this 
species must belong to the genus CalUptcrvs, and therefore cannot be 
Monellia caryeUa (Fitch). However, the author has not had an 
opportunitj- to study this carefully, so leaves it as it is, calling this 
California species Monellia caryella (Fitch). 

Because of the fact that all the species of aphids on walnut are 
so closely related, and so very similar in structure, a key to separate 
them, one from another, is given here. This key is adapted from 
Davidson.^ 

1. Cornicles quite evident, about as long as wide. 

Chromaphis juglandlcola (Kalt.) 
— ■ Cornicles barely perceptible, considerably wider than long 2 

2. Tibiae of alate viviparae entirely dusky CaUipterus caUfornicus (Essig) 

— Tibiae of alate viviparae mostly pale - 3 

3. VI spur longer than VI base. Oviparous females with four longitudinal rows 

of capitate hairs CalUpterus caryae Monell 

— VI spur shorter than VI base. Oviparous females with six longitudinal rows 

of capitate hairs MoneUia caryella (Fitch) 



11. Genus Callipterinella Van der Goot 

Van der Goot, Zur Systematic der Aphiden, 1913. Type Aphis (CalUpterus) 
ietulariv^ Kaltenbaeh. 

27. Callipterinella annulata (Koch) 

Koch, Die Pflanzenlause, p. 1855. Chaitophorus (orig. desc). 
Gillette, Jour. Econ. Ent., vol. 3, p. 367, 1910, Chaitophorus hetulae (Buck- 
ton) (list). 
Davidson, Jour. Econ. Ent., vol. 10, p. 292, 1917 (desc). 

Becords. — Betula alba; Oakland, Walnut Creek (Davidson). 

This species has been reported by Davidson as infesting the leaves 
and shoots of the white birch in the San Francisco Bay region. It is 
unknown to the author. 



8 Ibid., p. 35. 



32 MISCELLANEOUS STUDIES 

Tribe Chaitophorini Wilson (Lachnidea Mordw. and 
Chaitopheri Mordw.) 

Wilson, Can. Ent., vol. 42, pp. 385-387, 1910. 

This tribe as considered by Wilson contains the following genera : 
Arctaphis, Chaitophorus, Symydobius, Thomasia, and Sipha. The 
author has followed Wilson's classification, having added, however, 
two genera described later by Essig: viz., Micrella and Fullawaya. 
Essig's genus Eichochaitophorm is a synonj-m of Arctaphis Walker 
(see discussion under no. 27). Mordwilko's groups Lachnoidea and 
Chaitophori are both included in this one tribe. In the former, Mord- 
wilko includes Symydobivs and Pterochloriis, and in the latter, 
Cl'Odobius, Mfl-anoxanthiis, and Chaitophorus. Botli Cladobius and 
Melanoxanthus are included in this paper in the tribe Pterocomniini, 
being synonyms of the genus Pteroconima Buckton. Following is a 
description of tlie tribe Cliaitophorini as given by Wilson {op. cit.) : 

Antennae, except in Sipha, always six-segmented ; in Siplia there are but five. 
Length variable; antennal tubercles wanting; antennae, legs, and body covered 
with hair-like bristles. Fore wings with two oblique veins and cubitus always 
twice forked; hind pair with two cross veins. Nectaries (cornicles) variable in 
length and size, but never longer than one-tenth the length of the body. The 
genera in this tribe are somewhat similar to those in the tribe Callipterim, but 
are easily distinguished by the shorter and heavier antennae and legs, as well as 
by the finer and more hair-like bristles. 

The following kej' to the Californian genera has been adapted from 
Wilson and E.ssig: 

1. Spur of sixth antennal segment at least three times as long as the segment 2 

— Spur not three times as long as the segment. Cauda broadly rounded and 

without knobbed tip 4 

2. Spur more than five times as long as the segment; cornicles longer than the 

base of the sixth segment Chaitophorus Koch 

— Spur of sixth segment not more than five times as long as the segment; corn-. 

icles not. longer than the base of the sixth segment 3 

3. Cauda a knob on a quadrangular base (fig. 69). Spur about five times as 

long as sixth segment Arctaphis Walker 

— Cauda tapering to a blunt tip which is usually straight across, not being 

rounded or constricted at the base (fig. 70). Spur but slightly more than 
three times as long as the sixth segment _ Micrella Essig 

4. Spur of sixth segment shorter or scarcely longer than the segment; antennae 

nearly as long as the body Symydobius Mordwilko 

— Spur considerably longer than sixth segment; antennae about one-half the 

length of the body 5 

5. Cornicles absent; body with lateral tubercles Fullawaya Essig 

— Cornicles present; lateral body tubercles wanting Thomasia Wilson 



A SYNOPSIS OF TEE APHIVIDAE 33 

GeiiTis Chaitophorus Koeli 
Koch, Die Pflanzenlause, p. 1, 1854. Type Apliis accris Linn. 

Tlu're are at present no .species of this genus in California; most 
of the species hitherto placed in it are now considered as belonging 
to the genus Thomasia Wilson. 



12. Genus Arctaphis Walker 
Walker, The Zoologist, p. 2000, 1870. Type aphis populi Linn. 

This genus as defined by Wilson is represented in California by 
two species: A. viminalis (Monell) and A. popiilifolii (Essig). The 
latter was placed by Essig in a new genus, Eichocliaitophorus, but 
there is not enough difference between these to warrant a new genus. 

Key to California Species 

1. Wings hyaline. Three-nine large sensoria on third antennal segment (fig. 71). 

IV half as long against as V populifoUi (Essig) 

— Wings subhyaline. About ten rather small sensoria on III. IV but very 
little longer than V viminalis (Monell) 



28. Arctaphis populifolii (Essig) 

Figures 69, 71 

Essig, Pom. Jour. Ent., vol. 4, p. 722, 1912. Eichocliaitophorus (orig. 

dese.). 
Davidson, Jour. Econ. Ent., vol. 3, p. 37-5, 1910. Chaitophorus populifoliae 
(Fitch) (desc. male). 
Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911. Chaitophorus populifoliae 

(Fitch) (list). 

Records. — Populus trichocarpa, Santa Paula (Essig), Berkeley, September, 
1915; Populus fremontii, Stanford University and Penryn, Placer County (David- 
son) ; Menlo Park, San Mateo County, October, 1914 (Morrison) : Berkeley, Sep- 
_tember, 1915; El Cajon, San Diego County, June, 1916; Riverside, October, 1916. 

In 1912 Essig described this species from specimens taken on 
Populus trichocarpa at Santa Paula, and placed it in a new genus, 
Eichochaitophorus. He separated this genus from Arctaphis for the 
following reasons : 

According to Wilson the Cauda [in Arctaphisl is a knob on a quadrangular 
base. The anal plate is broadly rounded. In the new genus [Eich-ochaitophorus] 
the style has a distinct neck and is situated on a very distinct conical base. The 
anal plate is deeply notched in the middle so as to make it somewhat forked as 
in the genus Callipterus, 



34 MISCELLANEOUS STUDIES 

Although the anal plate is somewhat notched, there is scarcely 
difference enough to warrant the forming of a new genus. In fact, 
in many specimens one cannot tell whether or not a notch is present. 
As to the Cauda, consisting of the tip, a distinct neck, and a distinctly 
conical base, this is not greatly different from a cauda consisting of 
a knobbed tip on a quadrangular base. The only practical difference 
is in the base, being conical in one and quadrangular in the other. In 
populifolii (E.ssig) the base seems to be conical, yet one cannot be 
certain unless the specimen is mounted exactly. 

This species, A. populifolii (Essig), as stated above, was described 
from specimens taken on Populus trichoC'arpa at Santa Paula. In 
1910 Davidson found a species on Populus fremonti at Stanford Uni- 
versity, and the following j-ear at Penryn, Placer County, which he 
listed as Chaitophorus popitlifoliae (Fitch). A careful studj' of 
specimens from Davidson and the cotj'pes of Essig 's species convinced 
the author that they were identical. Morrison writes that Davidson's 
specimens are not C. populifoUae (Fitch), so Essig's species is distinct. 
In September, 191.5, the author obsei'ved a great number of specimens 
of this species on a weeping elm (Ulmus sp.) in Berkele.y, which was 
in close proximity to some populars. However, none were seen to be 
feeding on the elm, all being restless and wandering over the leaves 
and branches. In southern California this is often found infesting 
the empty galls of Thecabius popiiUmonilis Riley, such having been 
observed in San Diego and Riverside counties. 



29. Arctaphis viminalis (Monell) ? 

Monell, TJ. S. Geol. Geog. Surv., Bull. 5, p. 31, 1879. Callipterus (orig. 

desc). 
Clarke, Can. Eiit, vol. 35, p. 248, 1903. Chaitophorus (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 375, 1910. Chaitophorus (list). 
Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. Chaitophorus (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 716, 1912. Tliom-asia (list, key to Califor- 

nian species of Thomasia). 
Patch, Maine Agr. Exp. Sta., BuU. 213, p. 80, 1913. Chaitophorus (desc.). 

Records — Sali-x spp. ; Watsonville, Santa Cruz County, and Newcastle, Placer 
County (Clarke) ; Penryn, Placer County, and Stanford University (Davidson). 

This species has been reported from Placer, Santa Clara, and 
Santa Cruz counties on various species of willow. The true Chai- 
tophonis viminalis Monell is an Arctaphis, but whether or not the 
western species is the same as the eastern is a question. The author 
has never seen specimens of either and is therefore unable to make 



A SYNOPSIS OF THE APHIDIDAE 35 

any further coniment. He once thought the western species was iden- 
tical with Thomasia salicicola (Essig), to which Morrison considers 
it very closely related, but Davidson assures him the two are distinct. 

13. Genus Micrella Essig 

Essig, Pom. Jour. Ent., vol. 4, p. 71fi, 1012. Type if. vioncUa n.sp. 

30. Micrella monella Essig 

Figures 70, 72 
Essig, Pom. Jour. Eut., vol. 4, p. 717, 1912 (orig. desc). 
Secords. — SaUx lasuAepis, Oxnard (Essig) ; S. laevigata, Santa Paula (Essig). 

This species wa.s taken twice by Essig, who described it, in 1910 
near Oxnard, and in 1911 near Santa Paula. Since then it has never 
again been found. The author has had access to cotype specimens in 
Essig 's collection. 

14. Genus FuUawaya Essig 
Essig, Pom. Jour. Ent., vol. 4, p. 735, 1912. Type F. saliciradicis n.sp. 
31. FuUawaya saliciradicis Essig 

Figure 7.5 
Essig, Pom. Jour. Ent., vol. 4, p. 737, 1912 (orig. desc). 
Eecord. — Salix laevigata, Santa Paula, August, 1911 (Essig). 

On the roots of willow near Santa Paula, Essig once found a large 
number of aphids, the greater part of which were apterae, although 
a few alates were present. Unable to identifj' them with any known 
species, or to fit them into anj' genus, he described tliem as this species. 
Since tlu'U they have not been taken. The author has had access to 
cotype specimens in Essig 's collection. 

15. Genu.s Thomasia Wilson 
Wilson, Can. Ent., vol. 42, p. 386, 1910. Type Chaitophorus populicola Thomas. 

This genus is separated from Chaitophorus principally by the 
comparative lengths of the antennae and the comparative lengths of 
the spur of the sixth antennal segment. In Chaitophorus (type Aphis 
aceris Linn.) the antennae are almost as long as the body, and the 
spur of the sixth segment is over five times as long as the base. In 
this genus the antennae are but about one-half as long as the body, 
and VI spur is but slightly longer than VI base. 



36 MISCELLANEOUS STUDIES 

Key to California Species 

1. Wings hyaline 2 

— Wings with veins clouded (fig. 273) populicola (Thomas) 

2. Ill longer than VI (including spur) negundinis (Thomas) 

— Ill not longer than VI (including spur) 3 

3. IV with secondary sensoria crucis Essig 

— IV without secondary sensoria salicicola Essig 



32. Thomasia crucis Essig 

Figure 7(5 
Essig, Pom. Jour. Ent., \ol. 4, p. 742, 1912 (orig. desc). 
Secords. — Salix macrostaoluia, Santa Paula, August, 1911 (Essig). 

Essig once found this species ou the leaves of willow near Santa 
Paula. Since then it has never again been taken. The author has 
had access to cotype specimens in Essig 's collection. 

33. Thomasia negundinis (Thomas) 

Thomas, 111. Lab. Nat. Hist., Bull. 2, p. 10, 1878. Chaitophorus (orig. 

desc). 
Sanborn, Kan. Univ. Sei., Bull. 3, p. 3."), 1904. Chaitophonui (desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 37fi, 1910. Chaitophonis (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 716, 1912 (list). 

Records. — Acer negundo, Stanford University (Davidson); Salt Marshes, Palo 
Alto, May, 1912 (Morrison). 

This species of Thomasia is quite common on box elder in the 
vicinity of Stanford University and Palo Alto. The author has never 
taken specimens, nor had access to any. Morrison writes that 
although lie has never had access to eastern specimens of T. negundinis 
(Thos.) for comparison he is not able to convince himself that the 
western species is negundinis. The author is unable to form any 
opinion at present, having never seen specimens, hence lists the species 
as Davidson has done. 



3-t. Thomasia populicola (Thomas) 

Figures 77, 275 

Thomas, 111. Lab. Nat. Hist, Bull. 2, p. 10, 1878. Chaitophonis (orig. 

desc. ) . 
Essig, Pom. Jour. Ent., vol. 1, p. 98, 1909. Chhitophorus (desc). 
Essig, Pom. Jour. Ent., vol. 4, p. 716, 1912 (list). 

accords. — Populus s-pp., Salix spp., Santa Paula (Essig) ; Riverside, May, 1917; 
Populus sp.. Canton, Broadwater County. Montana, July, 191.5, E. W. Haegele; 
Edna Canon, Boxelder County, Utah, August, 1916, R. W. Doane. 



A SYNOPSIS OF TSE APHIDIDAE 37 

This species has been reported by Essig from Ventura County. 
The author lias never taken tlie alatcs, but has had the opportunity 
of examining Essig's specimens, and specimens from Montana and 
Utah taken by Haegele and Doane. It is easily distinguished from 
other members of the genus bv the broad, dark wing veins. 



35. Thomasia salicicola (Essig) 

Figure 78 

Essig, Pom. Jour. Ent., vol. 3, p. 532, 1911. Chaitophorus (oi'ig. desc). 
Davidson, Jour. Eeon. Ent., vol. 3, p. 375, 1910. Chaitophorus nigrae Oest- 

hmd (?) (list). 
Davidson, Pom. Jour. Eut., vol. 3, p. 398, 1911. Chaitophorus nigrae Oest- 

lund (?) (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 619, 1912 (note). 
Essig, Pom. Jour. Ent., vol. 4, p. 716, 1912 (list). 

Becords. — Salix laevigata, Santa Paula (Essig), Salix nigra, Lakeside, San 
Diego County, April, 1916; Populus trichocarpa, Santa Paula (Essig); Salix sp., 
San Jose, Stanford University, Penryn, Placer County (Davidson), Fillmore, Ven- 
tura County, March, 1911 (Essig). 

Essig reported this from Ventura Count}', and the author has 
found it in San Diego County. It was observed to be in large colonies 
on the leaves and leaf petioles of the tender growth of willow, in 
company with Siphocorijne carpreue (Fabr.). Specimens taken by 
Davidson and listed as Chaitophorus nigrae Oestlund prove to be 
identical with this species. 



16. Genus Symydobius Mordwilko 

Mordwilko, Rap. Lab. Zool. Kap. Imp. Varch. Univ., 1895. Type Aphis 
oblonga Heyden. 

Key to California Species 

1. Anal plate half-moon-sliaped 2 

— Anal plate bilobed (fig. 271) ; cornicles pale, appearing white in life; antennae 

ivith about six to eight secondary sensoria on III, and one or two on IV 
(fig. 272 ) chrysolepis Swain 

2. Spur of VI but a short thumb-like projection; sensoria on III numbering about 

six to ten; none on IV agrifoliae Essig 

— Spur of VI longer, being equal to or longer than base of VI ; fifteen to twenty 

sensoria on III, one or two on IV (figs. 73, 74) 3 

3. Antennae for the most part dark, being dark brown or black; spur and base 

of VI equal, lateral abdominal tubercles present in aptcrae. 

macrostachyae Essig 

— Antennate for the most part pale, being light brown or amber; spur of 

VI usually slightly longer than base ; apterae without lateral abdominal 
tubercles sallcicorticis Essig 



38 MISCELLANEOUS STUDIES 

36. Symydobius agrifoliae Essig 

Essig, Univ. Calif. Publ. Entom., vol. 1, pp. 311-317, 1917 (orig. desc). 
Records. — Quercus agrifolia; Santa Paula (Essig). 

This interesting aphid was taken in Ventura County on live oak 
during 1911. It differs from other members of this genus in the 
extremely short spur of the sixth anteunal segment. The coloration 
is very similar to that of the next species, but the length of VI spur 
and the fact that the anal plate is not bilobed serves to distinguish it. 



37. Symydobius chrysolepis Swain 
Figures 269 to 274 
Swain, Trans. Am. Ent. Soc, vol. 44, p. 6, 1918 (orig. desc). 
Eecords. — Quercus chrysolepis; Alpine, San Diego County (Swain). 

This is a medium sized, brownish colored aphid found in 1916 
infesting the terminal twigs and leaf petioles of maul oak in San 
Diego County. Its pale white cornicles are very conspicuous, and 
serve as a distinguishing character. The anal plate is bilobed, a char- 
acter not found in other members of the genus, and one which may 
be sufficient for the separation of the species (and S. albuiphus Davis, 
in which the anal plate is also bilobed) from Symydobius into a new 
genus. However, the author believes it best to retain them in this 
genus at present.. The apterous females were found to be heavily 
parasitized by the chalcid fly, Clostcrocerus utahomis Crawford var. 
californicus Girault. 



38. Sjonydobius macrostachyae Essig 
Figure 73 
Essig, Pom. Jour. Ent., vol. 4, p. 727, 1912 (orig desc). 
Records. — Salix macrostachi/a ; Santa Paula (Essig), Fresno, June, 1915. 

Twice has this species been taken, once by Essig near Santa Paula 
and once by the author along the San Joaquin River near Fresno. 
It is found in fairly large colonies on the younger stems of willow. 
These colonies consist for the most part of apterae, only a very few 
alates being present. 



A SYNOPSIS OF THE APHIDIDAE 39 

39. Symydobius salicicorticis Essig 

Figure 74 
Essig, Pom. Jour. Ent., vol. 4, p. 731, 1912 (orig. desc). 
Jtecord. — Salix laevigata; Santa Paula (Essig). 

Together with specimens of Fullawaya saliciradicis Ftssig, this was 
taken on willow along the Santa Clara River near Santa Paula in 
August, 1911. The colonies are found on the bark near the surface 
of the ground either just above or just below it. Essig reports that it 
is preyed upon quite extensively by the larvae of an undetermined 
species of syrphus fly. The author has had access to cotype specimens 
in Essig 's collection. 



Group Lachniria Passerini 

Passerini, Gli Afidi, 1860. 

In this group there are included two tribes, Lachnini Del Guercio 
and Pteroeommini "Wilson, following "Wilson. Mordwilko places but 
the one tribe Lachnini in this group, including the genus Pterocamma 
Buckton in the tribe Chaitophori. However, to the author the group- 
ing followed here seems more natural. The following key is adapted 
in part from Borner (Sorauer, Pflanzenkrankheiten, vol. 3, p. 665, 
1913) : 

Sixth antennal segment with a short, thick (thumb-like) projection. Cornicles 
conical (fig. 91) or wart-like. Empodial hair short, and oftentimes indistin- 
guishable (fig. 79) Tribe Lachnini 

Sixth antennal segment with a slender projection (VI spur) which is about as 
long as the segment (VI base). Cornicles cylindrical or clavate (figs. 81, 82). 
Empodial hair practically as long as the claws (fig. 80). Tribe Pteroeommini 



Tribe Pteroeommini Wilsoii 

Wilson, Ann. Ent. See. Am., vol. 8, pp. 347-358, 1915. 

This tribe, as considered by Wilson, contains but the one genus, 
Pterocamma Buckton. In a former paper (Can. Ent., vol. 43, p. 384, 
1910) he recognized two genera: the one, Melanox-antherium Schoute- 
den, in which the cornicles were swollen or vasiforai, and the other, 



40 MISCELLANEOVS STUDIES 

Pterocaiiuna Buekton, in which the cornicles were cylindrical. He 
states in his later paper : "... after having further studied the group 
I am of the opinion that such a divsion is illogical, and if a division 
is necessary each species should form a different genus. It, therefore, 
seems more practical to confine all the species to a single genus. ' ' The 
characters of this tribe and genus are as follows : 

Antennae with six segments and reaching near the base of tlie abdomen. 
Wings normally with venation as in Aphis. Nectaries [cornicles] short, but 
clavate. Cauda short and broadly rounded at the tip as in Lachnini. Entire 
body, antennae, and legs covered with long hairs as in Lachnini. As has already 
been pointed out by Oestlund, this group appears intermediate between the Ch-aito- 
phorini and the Lachnini. Their habits and actions being in different ways similar 
to both. 



17. Genus Pterocomma Buekton 

Buekton, Monog. Brit. Aphides, vol. 2, p. 143, 1879. Type P. pilosa 
Buekton. 

Key to California Species 

1. Cornicles abruptly constricted at distal end, and without a distinct flange 

(fig. 81), the diameter of the opening being less than the diameter of the 
smallest part of the cornicle. Wing veins broad and shaded. 

flocculosa (Weed) 

— Cornicles not so abruptly constricted and with a distinct flange. Wing 

veins normal 2 

2. Cornicles about twice as long as their greatest diameter ....smithiae (Monell) 

— Cornicles considerably longer than greatest diameter, and longer tlian hind 

tarsus populifoliae (Fitch) 



40. Pterocomma flocculosa (Weed) 
Figure 81 

Weed, Insect Life, vol. 3, p. 291, 1891. Melanoxaiitlius (orig. desc.). 
Wilson, Ann. Ent. Soc. Am., vol. 8, p. 350, 1915 (desc). 

Records. — Salix sp., Berkeley, March, 1915; 1916 (Essig). 

In his paper on Pterocomma Wilson states that this species does 
not occur on the Pacific Coast. However, in March, 1915, the author 
found it rather abundantly on willow on tiie campus of the University 
of California in Berkeley. During the 1916 season Essig observed it 
to be quite common in Berkeley. Tlie species is easily recognized in 
life by the white cottony flocculence covering the colonies on the bark. 



A SYNOPSIS OF THE APHIDIDAE 41 



41. Pterocomma populifoliae (Fitch) 

Figures 82, 83 

Fitch, Cat. Homop. N. Y., p. 66, 1851. Aphis (orig. desc). 

Davidson, Jour. Econ. Ent., vol. 2, p. 300, 1909. Cladobius rufuhis n.sp. 

(desc). 
Davidson, Jour. Econ. Eut., vol. 3, p. 375, 1910. Cladobius rufulus Dvdn. 

(list). 
Essig, Pom. Jour. Ent., vol. 4, p. 786, 1912. Melanoxantherium rufulum 

(Dvdn.) (desc). 
Wilson, Ann. Ent. Soe. Am., vol. 8, p. 353, 1915. Pterocomma populca 

(Kalt.) (desc). 
Baker, Can. Ent., vol. 48, pp. 280-282, 1916 (desc). 

Eecords. — Salix sp. ; Stanford University (Davidson); Santa Paula (Essig); 
Walnut Creek, March, 1915 (Davidson) ; Grossniont, San Diego County, March, 
1916; Lakeside, San Diego County, April, 1916; Stanford University, May, 1912 
(Morrison); Populus sp. ; Stanford University (Davidson); Palo Alto, March, 
1915; Populus caroliniana, Banning, Riverside County, April, 1917. 

Tliis is a widely distributed species in California on various species 
of poplars and willows. Davidson first found it in 1909, describing 
it as a new species. In 1915 Wilson stated that it was synonymous 
with P. populea (Kalt.), but specimens sent him by the author he 
determined as P. bicolor (Oestlund). According- to his paper the 
cornicles of populca (Kalt.) are about equal in length to the hind 
tarsi. Californian specimens have the cornicles considerably longer 
than the hind tarsi, but not twice as long as he states they are in 
iicolor (Oestlund). His figures of the antennae show that in populca 
VI base and spur are subequal, and in bicolor the spur is considerably 
longer than the base. The latter is true for the Californian species. 
His color notes of populra fit the Californian species very well. Baker 
identified Aphis populifoliae Fitch as a Pterocovimu and places 
rufulus (Davidson) as a synonym. From a study of specimens taken 
in Santa Paula, Grossmont, Lakeside, Stanford University, and Wal- 
nut Creek, the author finds that Baker's description of populifoliae fits 
this species verj' well. Below are the measurements in microns of 
four alate specimens, together with the measurements of cornicles, 
antennae, and hind tarsi of one from Lakeside. (This was preserv'ed 
for several months in alcohol before being mounted for study, and had 
shrunk considerablj'. ) 

An examination of the following table shows that in the California 
specimens the cornicles are always considerably longer than the hind 
tarsi, but never twice as long, and that the spur of six is always longer 
than the base, except in one case. This specimen is considerably 



42 



MISCELLANEOUS STUDIES 



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A SYNOPSIS OF THE APHIDIDAE 43 

smaller than the others and has many more secondary sensoria, being 
a male. From this evidence this species is the same as Baker lists as 
P. populifoliae (Fitch) and should be so considered. The author has 
reared a number of specimens of a species of Aphidius from material 
obtained near Stanford University in May, 1915. 

42. Pterocomma smithiae (Monell) 

Moiiell, U. S. Geol. Geog. Surv., Bull. 5, p. 32, 1879. Cliaitophorus (orig. 

desc). 
Davidson, Jour. Ecou. Eut., vol. 2, p. 300, 1909. Cladobius salicti (Harris) 

(list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 375, 1910. Cladobius salicti (Harris) 

(list). 
Essig, Pom. Jour. Eut., vol. 4, p. 780, 1912. Melanoxantherium salicti 

(Harris) (list). 
Wilson, Ann. Ent. Soc. Am., vol. S, p. 3.55, 1915 (desc). 

Mecctrds. — Salix spp., Stanford University (Davidson, Morrison). 

Both Davidson and Morrison have taken this species in the vicinity 
of Stanford University on various species of willow. According to 
Wilson, with whom Morrison and Baker agree, this is P. smithiae 
(IMonell), the salicti of Harris being synonymous. The sexuales were 
observed by Davidson in October, the eggs hatching in January. 



Tribe Lachnini Del Guercio 

Del Guercio, Redia, vol. 5, 1908. 

This tribe is represented in California by three genera, viz., Essig- 
ella Del Guercio, Tubcrolachnus Mordwilko, and Lachmts Burmeister, 
while there are six genera included in the tribe as it is here considered. 
Following is a brief characterization of the tribe adapted from Mord- 
wilko: 

The body and appendages are very hairy, and usually quite large. The eauda 
is absent, the cornicles cupola-shaped, being black or brown in color. Sometimes 
they are reduced to mere pores or not fully developed [Lachnus taxifoUa Swain]. 
The antennae in general are not longer than the head and thorax, six-jointed 
[except in Essigella Del Guercio], with the spur of the sixth segment very short, 
not being as long as the segment itself. The beak is almost always elongated, 
generally reaching to or beyond the middle of the abdomen. All this group possess 
the anatomical peculiarity that the narrowed hind end of the stomach is covered 
with the intestine. The stigma of the fore wing is elongate linear [in Longi- 
stigma Wilson it reached past the tip of the wing (fig. 89)]. The cubitus is twice- 
branched. 



44 MISCELLANEOUS STUDIES 

All the California species with the exception of Tuberolachnus vimi- 
nalis (Fonsc), which lives on willow, are found on eouifei-s — Piims 
sp., Pseudotsuga sp., or Picea sp. 

Following is a key to the genera, adapted from Del Guercio, Wil- 
son and Essig. In this key are included not only the California 
genera but the other three as well, in that an understanding of the 
characters is thus made easier. 

1. Antennae six-segmented - 2 

— Antennae five-segniented (fig. 83) Essigella Del Guercio 

2. Stigma exceptionally long, reaching beyond the tip of the wing (fig. 84). 

Longistigma (Wilson) 

— • Stigma not exceptionally long, not reaching beyond tlic tip of the wing 

(fig. 85) " - 3 

3. First joint of the hind tarsus much shorter than half the second (fig. 86) .... 4 
— ■ First joint of the hind tarsus equal to or slightly longer than half the second 

(fig. 87) Eulachnus Del Guercio 

4. Abdomen with horn-like tubercle on median dorsum between the cornicles, 

(Sometimes this cannot be made out in specimens mounted in balsam, but 
it is always readily discernible in fresh or alcoholic material). 

Tuberolachmus Mordwilko 

— Abdomen without horn-like tubercle 5 

5. Bases of first and second discoidal close together; third discoidal often very 

faint; wings slightly if ever clouded (fig. 85) Lachnus Burmeister 

— Bases of first and second discoidals not so close together as in Lachnus Burm. ; 

third discoidal plain ; wings often darkly clouded Pterochlorus Bondani 



18. Genus Essigella Del Guercio 

Del Guercio, Eer. di patal. veg., vol. 3, p. 328, 1909. Type Lachiius cali- 
fiirnicus Essig. 

43. Essigella californica (Essig) 

Figures 3, 5, 83 

Essig, Pom. Jour. Ent., vol. 1, p. 1, 1909. Larhnus (orig. desc). 

Del Guercio, Pom. Jour. Ent., vol. 1, p. 73, 1909 (translation by C. F. 

Baker of Del Guercio 's paper listed above). 
Essig, Pom. Jour. Ent., vol. 4, p, 773, 1912 (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 780, 1912 (desc). 

Becords. — Pinus radiata; Claremont, Los Angeles County, and Santa Paula 
(Essig); Pinus saiiniana, Stanford University, March, 1915; Finns spp., Stan- 
ford University, March and April, 1912 (Morrison) ; Ontario, San Bernardino 
County, January, 1917. 

This curious little aphid, described b.y Essig from specimens taken 
in Claremont, Los Angeles County, on Pinus radiata, has since been 
found in several parts of the state. "Wilson has taken it in Oregon 
on Pseudotsuga taxifolia, and Patch in Maine on Pinus strobus. It 



A SYNOPSIS OF THE APHIDIDAE 4S 

is a small, slender, long-legged aphid, that clings fast to the pine 
needles and is extremely difficult to see. However, if a branch of 
pine is struck sharply and with considerable force over a white paper 
or cloth, a large number of these aphids will jar off. 

19. Genus Tuberolachnus Mordwilko 

Mordwilko, Ann. Mus. Zool. d. I'Acad. Imp. Sci., vol. 13, p. 374, 1908. 
Type Aphis viminalis Fonso. 

44. Tuberolachnus viminalis (Fonsc.) 

Figure 8(5 

Boyer de Ponscolmbe, Ann. Ent. Soc. France, vol. ]0, p. 162, 1841. Ai>liis 

(orig. desc). 
Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. Laehnus (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Laehnus (list). 
Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. Laehnus dentatus Le 

Baron (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 774 (772), 1912 (list). 

Records. — Salix spp., Stanford University and Penryn, Placer County (David- 
son) ; Ventura County (Essig); Stanford University, November, 1914; Berkeley, 
July, 1915; Eiverside, July, 1916. 

This extremely large aphid, which lives in large colonies on the 
branches of various species of willows, is found throughout the San 
Francisco Bay region, Sacramento Valley, and southern California, 
although it is not at all common. Davidson reports considerable 
parasitization by a species of Epherdkis, and Essig infection from 
some bacterial or fungus disease. The large size and the presence of 
a dorsal abdominal tubercle are distinguishing characters. 



20. Genus Laehnus Burmeister 

Burmeister, Handbuch d. Entomologie, p. 91, 1835. Type Laehnus fadatus, 
n.sp. 

This is the third largest genus of aphids in regard to the number 
of species in California. All the species are to be found on various 
conifers, usually feeding through the bark of the branches or trunk. 
Characters for distinguishing the species are hard to obtain, and 
those used by the author in the following key are of no value except 
with specimens of the alate viviparae. This key is not at all adequate, 
and is offered here merely as an aid. The author understands that 
Wilson is preparing a monograph of this genus, which will undoubt- 
edly prove quite valuable. 



46 MISCELLANEOVS STUDIES 

Key to California Species 

1. Beak reaching considerably beyond the third coxa 2 

— Beak at most bareh' reaching to the third coxa 8 

2. Beak reaching almost to or even beyond the tip of the abdomen 3 

— - Beak not reaching to the tip of the abdomen 4 

3. First joint of hind tarsus more than cue-third as long as the second joint. 

Legs black except the base of the femora and a broad ring near the base 
of the tibiae ponderosa Williams 

— First joint of hind tarsus scarcely more than one-fourth as long as the second 

joint. Legs pale at the base of the femora and tibiae, black at tips. 

oregonensis Wilson 

4. Body exceptionally large, being over 4 mm. long, usually about 5 mm., and 

over 2 mm. wide _ 5 

— Body of average size, being from 2.5 mm. to 3 mm. long, and from 0.73 to 

1.2 mm. wide 7 

5. Third segment of antennae with many sensoria (eight or more), (figs. 88, 

89) ; 6 

— Third joint of antennae with but few or no sensoria, at most with one or two. 

First joint of hind tarsus a little less than half as long as the second. 
On Finns sabiniana sabinlanus n.sp. 

6. Third joint of antennae with about 8rl2 sensoria (fig. 88). Tibiae with a pale 

ring near the base. First joint of hind tarsus scarcely more than one-third 
the length of the second. On Picea sp vanduzei n.sp. 

— Third joint of the antennae with 19-20 sensoria (fig. 89). Tibiae without 

pale ring near base. First joint of hind tarsus almost one-half the length 
of the second. On Pinus sp. and Abies sp ferrisi Swain 

7. Beak not reaching to the middle of the abdomen. Segment three of the 

antennae almost as long as the fourth, fifth, and sixth together. Apex 
of stigma meeting the margin of the wing in an acute angle, and not 
terminated by a distinct vein (fig. 92). On Pseudotsuria iaxifoUa. 

pseudotsugae Wilson 
— • Beak reaching beyond the middle of the abdomen. Third antennal segment 
not nearly so long as the fourth, fifth, and sixth together. Apex of stigma 
meeting the wing margin in an obtuse angle, and terminated by a distinct 
vein (fig. 93). Apterous viviparous females with a distinctive pattern on 
dorsum of abdomen. On Thuya occidentalis tujafilinus (Del Guercio) 

8. First joint of hind tarsus longer than one-fourth the second 10 

— ■ First joint of hind tarsus less than one-fourth the second 9 

9. Third antennal segment without sensoria (fig. 94). Body robust, being of the 

usual Lachnus shape. Third discoidal twice-branched, only occasionally 
once-branched. On Abies grandis occidentalis Davidson 

— Third antennal segment with several irregular sensoria (fig. 9.")). Body long 

and narrow, being somewhat the shape of Essigella californica (Essig). 
Third discoidal simple or once-branched. On Pinus sp. 

pini-radiatae Davidson 
10. Cornicles very poorly developed, seemingly absent in some cases (fig. 103). 
Segment three of antennae with five-seven large circular sensoria which are 
hardly distinguishable (fig. 106). On Pseudotsuga taxifolia. 

taxifolia Swain 

— Cornicles normal (fig. 97), being quite conspicuous. Third antennal segment 

with two-four clearly defined sensoria (fig. 101). On Picea glehni. 

glehnus Essig 



A SYNOPSIS OF THE APHIDIDAE 47 

45. Lachnus ferrisi Swain 
Figures 89, 91 

Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. Lachnus ahietis Fitch 

(list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Lachnus niittis Fitch 

(list). 
Eseig, Pom. Jour. Ent., vol. 4, p. 773, 1912. Laohnus ahietis Fitch (list). 
Swain, Trans. Am. Ent. Soc, vol. 44, p. 9, 1918. 

Kecords. — Allies concolor, Stanford University (Davidson) ; Pi7ius sp., Stan- 
ford University (Swain). 

This large laclniid, recently described by the author, has been 
found only in the vicinity of Stanford University, in 1909 and 1910 
by Davidson on lowland fir, and in 1915 by Ferris on some young 
pine trees. Since then it has not been observed. 



46. Lachnus glehnus Essig 
Figures 96, 97 
Essig, Pom. Jour. Ent. Zool., vol. 7, pp. 180-187, 1915 (orig. desc). 
Becord. — Picea glehni, Sacramento (Essig). 

Essig described this species from specimens taken on a Japanese 
spruce in Capitol Park, Sacramento, in 1912. At the time it wa-s so 
abundant that control measures were deemed necessary'. The author 
has had access to the type specimens in E.ssig's collection. 



47. Lachnus occidentalis Davidson 

Davidson, Jour. Eeon. Ent., vol. 2, p. 300, 1909 (orig. desc. apterae). 
Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910 (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912 (list). 
WUson, Can. Ent., vol. 44, p. 193, 1912 (desc. all forms). 

Becords. — Abies grandis, Stanford University (Davidson, Morrison, Ferris 
and the author) ; Ahies concolor, Corvallis, Oregon (Wilson). 

This species is practically always present on a lowland fir tree in 
the cactus garden of the Stanford University grounds. Wilson has 
found it in the vicinity of Corvallis, Oregon, on white fir. Davidson 
states that it is heavily preyed upon by the larvae of Syrphus arcuatus 
and Syrphus opinator. 



48 MISCELLANEOUS STUDIES 

48. Lachnus oregonensis "Wilson 
Wilson, Trans. Am. Ent. Soc., vol. 12, p. 103, 1915 (orig. desc). 
Becord. — Pinus contorta, Oregon and California (Wilson). 

There ha.s been no published record of tliis species from California. 
Wilson wrote the autlior some time ago that he had taken it in this 
state, although he gave no definite locality. The author has never seen 
specimens. 

49. Lachnus pini-radiatae Davidson 

Figure 95 

Davidson, Jour. Econ. Eut., vol. 2, p. 299, 1909 (orig. dese.). 
Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910 (list). 
Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911 (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912 (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 785, 1912 (descriptive note). 

Mecords. — Pinus radiata, Stanford University (Davidson), August, 1914, April, 
1915 (author), March, 1916 (K. B. Brown); Pimis ponderosa, Bowman, Placer 
County, November, 1911 (H. H. Bowman), Berkeley, March, 1915 (Geo. Shinji) ; 
Pinus sahiniana, Penryn, Placer County (Davidson). 

This is a fairlj' small, slender-bodied, long-legged lachnid found 
infesting the needles of various pines in the San Francisco Bay region 
and in the Sacramento Valley. They are easily recognized on the 
needles by the wliitisli mass of flocculenee which covers their bodies. 

50. Lachnus ponderosa Williams 

Figure 104 

Williams, Univ. Neb. Studies, vol. 10, p. 106, 1910 (orig. dese.). 
Davidson, Jour. Econ. Ent., vol. 7, p. 127, 1914 (list). 

Record. — Piyius ponderosa jeffreyi, Tallae, Eldorado County (Davidson). 

Davidson's is the onlj^ report of this species in California. The 
identification of his specimens was verified by Davis. One specimen 
the author saw was quite small, being much smaller than the others 
taken by Davidson. 



51. Lachnus pseudotsugae Wilson 
Figures 92, 98 
Wilson, Can. Ent., vol. 44, pp. 159, 302, 1912 (orig. dese.). 
Record. — Psetidotsuga taxifolia; Oregon, California (Wilson). 



A SYNOPSIS 01'' THE APHIDIDAE 49 

Wilson wrote tlie author some time ago that he had taken this 
species in California, although he gave no definite locality or collec- 
tion record. The autlior lias had the opportunity to study cotype 
specimens. 

52. Lachnus sabinianus n.sp. 

Eecord. — Pinus sahiniana, San Francisco (Compere). 

In March, 1915, Harold Compere of the California State Insectary 
found a small infestation of a species of Lachnus on Digger Pine in 
the Golden Gate Park, San Francisco. Since this one collection, the 
species has not again been observed. Being unable to identify the 
species with any described in America, a description is herewith 
appended, the species being named after its host plant, Pinus sabin- 
i-ana. All the specimens, including the types are in the collections 
of E. 0. Essig and of the University of California, Berkeley. The 
specimens were all mounted in Canadian balsam before color notes 
were taken, so those in tlie following description are only approxi- 
mately correct. 

Alate viviparous female. — Rich chestnut-amber to dark brown. 
Antennal segments I and II, amber; III, yellowish with tips darker; 
IV, V, and VI, dark yellow to dusky. Prothorax, chestnut-brown. 
Thoracic lobes very dark brown to black. Beak, pale with tips dusky. 
Cornicles, black. Cauda and anal plate with distal margins black. 
Femora, chestnut-brown with base amber; tibiae, brown with amber 
ring near the base ; tarsi, amber. Wing veins, grayffi stigma, dusky 
gray. 

Measurements: Body 4.2 mm. long and 1.7 mm. wide at thorax. 
Antennae reach to base of abdomen, without secondary sensoria. I, 
0.10 mm. ; II, 0.09 mm. ; III, 0.50 mm. ; IV, 0.25 mm. ; V, 0.19 mm. ; 
VI, 0.08 mm. ; total, 1.21 mm. Beak reaches to the base of the cor- 
nicles. Cornicles medium sized and of the usual Lachmts shape, 
being 

Apterous viviparous female. — Chestnut-brown in color with black 
dorsal spots on abdomen. Antennal segments I and II, dark; III, 
dusky yellow with tip dark; IV, V, and VI slightly darker. Beak 
reaches to the base of tlie cornicles. Coxae, black ; femora, black with 
basal one-fifth paler; tibiae, black with pale ring near base; tarsi, 
black. Cornicles, black and conspicuous. They measure 5.2 mm. in 
length and 3.3 mm. in width. 



50 MISCELLANEOVS STUDIES 

53. Lachnus taxifolia Swain 

Figures 99-103 

Swain, Trans. Am. Ent. Soc, vol. 44, p. 11, 1918. 

Secords. — Pxeudutsuga taxifolia, Sacramento (Essig), Berkeley and San Fran- 
cisco (Shinji). 

This is a fairly common species found in colonies on the branches 
and trunks of Douglas fir in the San Francisco Bay and Sacramento 
Valley. It is interesting pai-ticularly because of the atrophied cor- 
nicles. 



54. Lachnus tujafilinus (Del Guereio) 

Figures 93, 105 

Del Guereio, Kedia, vol. 5, p. 287, 1909. LachneiUa (orig. desc). 

Essig, Pom. Jour. Ent., vol. 3, p. 541, 1911. Lachnuj< juniperi DeGeer 

(dese.). 
Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912. Lachnus juniiieri DeGeer 

(list). 
Davidson, Jour. Econ. Eut, vol. 7, p. 127, 1914 (list). 

Records. — Thuya occidentalis, Claremont, Santa Paula (Essig) ; Palo Alto, 
Walnut Creek (Davidson); Stanford University, March, 1912 (Morrison); San 
Diego, March, 1916; Riverside, October, 1916, March, 1917. 

This oddly marked Lachnus is more or less common throughout 
California wherever arborvitae is cultivated. The apterous females 
are the most common, and are easily recognized by the odd markings 
on the dorsum of the abdomen (see Essig 's illustrations). Occasion- 
ally the alate females are found, Davidson finding some in April, 
Morrison and the autlior in March. The author has observed the 
larvae of CoccineUa calif ornica feeding on them in Riverside. 



55. Lachnus vanduzei n.sp. 

Figure 88 
Records. — Picea sp., Berkeley, September, 1914 (Essig, E. P., Van Duzee). 

In September, 1914, E. P. Van Duzee collected a few specimens 
of a large Lachnus on a species of spruce in Strawberry Canyon, near 
Berkelej\ Later in the same month Essig found specimens on the 
same tree. The following fall the atithor hunted for the species, 



/I SrXOPSIS OF THE APBIDIDAE 51 

but was imable to find any specimens, the tree on whieli it was first 
found liaving been cut down. In the following description the color 
notes are not absolutely accurate, as they were taken from material 
mounted in balsam. This species is named after its first collector, 
Mr. E. P. Van Duzee, of the University of California. Type speci- 
mens are in the eolUetion of tiie University of California. 

Alatc viviparous female. — The alate viviparous females are of a dark 
muddy color, as near as can be judged from the mounted specimens. 
The antennae are : 1 and II, dusky ; III and IV, pale with apical half 
dusky; V, pale witli the apex or apical third duskj^; VI, pale with the 
apex and sjiur dusky. The measurements of the segments are : I, 
0.09 mm.; II, 0.07 mm.; Ill, 0.5 mm.; IV, 0.26 mm.; V, 0.27 mm.; 
VI, 0.16 mm. The sensoria are located as follows: III, 10-12; IV, 
2-3; V, 2-3; VI, 1. They are large and circular, and quite evenly 
distributed in a line on each .segment. The beak reaches to the base 
of the Cauda. The coxae are black, the femora amber on the basal 
half and black on the apical, the tibiae are black with an amber ring 
near the base, the tarsi are black. The first joint of the hind tarsus 
is not one-third the length of the second, the first measuring 0.08 mm., 
and the second 0.26 mm. The wings are quite large, with a very 
distinct stigma. The costal vein is grayish-brown, the subcostal 
brown. The stigma is long and brown, the stigmal vein being pale 
brown and slightly curved throughout its entire length. Tlie first 
and second discoidals are distinct and pale brown, the second dis- 
coidal being slightlj' curved near the tip. The third discoidal is indis- 
tinct and twice-branched, the angles of the branches being very acute. 
Apterous viviparovs female. — Prevailing color, amber-brown, with 
the abdomen mottled gray, brown, and black. The head is brown 
with anterior margin amber. The antennae are colored as follows : 
I, amber; II, amber; III, amber with tip dusky; IV, amber with tip 
dusky; V, amber with apical two-thirds dusky; VI, dusky. The beak 
reaches to the base of the cauda. The femora are brown with the 
bases amber, the tibiae and tarsi brown. The fii*st joint of the hind 
tarsus is scarcely more than one-third the length of the second. In 
four tarsi measured, the relative lengths of the joints were : 0.07 to 
0.23 mm. ; 0.08 to 0.23 mm. ; 0.08 to 0.28 mm. ; and 0.07 to 0.25 mm. 
The cornicles are conspicuous and dark, the cauda well rounded and 
dark on its posterior edge. The lengths of the antennal segments are : 
I, 0.1 mm.; II, 0.1 mm.; Ill, 0.56 to 0.57 mm.; IV, 0.21 to 0.23 mm.; 
V, 0.22 to 0.28 mm. ; VI, 0.15 to 0.16 mm. 



52 MISCELLANEOUS STUDIES 

Group Aphidina Wilson 

Wilson, Ann. Ent. Soe. Am., vol. 3, p. 314, 1910. 

This group as considered by Wilson consists of three tribes : 
Trichosiphini, Macrosiphini, and Aphidini. The first of these con- 
tains two genera found onlj^ in the Asiatic islands, so it will not be 
considered in this paper. This group contains quite closely related 
genera, and in many cases it is quite hard to distinguish between 
them. Following is a brief extract from Wilson's paper (cited above) : 

In studying closely related genera the development of the external characters 
may be placed in five divisions: (1) the antennae and spur; (2) the antennal 
tubercles; (3) the development of the nectaries [cornicles]; (4) the development 
of the Cauda; (5) the development of the wing venation. In a gi-oup of insects 
as pliable as the present one, any one or two of these characters may be either 
under- or over-developed and it is necessary to place the genera according to the 
greatest development. Of all the characters which show this variation tlie wings 
show what may be true of all these characters. 

The two tribes have been separated from one another on the character 
of the antennal tubercles, as Wilson says in the same paper : 

The division is made between species with distinct antennal tubercles and 
those having none or at the most indistinct tubercles. However, should a certain 
species have distinct antennal tubercles with the other characters [of the Macro- 
siphini] wanting, then it would have to go into the next tribe [Aphidini']. 

The keys to the tribes and genera below have been formulated by the 
author, following, however, those of Wilson, Van der Goot, and 
Mordwilko. 

1. Antennal tubercles well formed. Antennae usually as long as or longer than 
the body. Apterae often with sensoria on the third antennal segment. 
Body never with lateral tubercles on the seventh abdominal segment. Cor- 
nicles variable but usually about one-fourth the length of the body or 

longer Tribe Macrosiphini 

— Antennal tubercles absent or more or less indistinct. Antennae seldom longer 
than the body. Apterae seldom with sensoria on the third antennal seg- 
ment. Body with lateral tubercles on at least the seventh abdominal seg- 
ment Tribe Aphidini 



Tribe Macrosiphini Wilson 

Wilson, Ann. Ent. Soe. Am., vol. 3, p. 314, 1910. 
To a large extent the author has followed Wilson in the placing 
of the genera, but in a few eases he has not. This is noticeable in 
To.Toptera, which is considered by Wilson as belonging to this tribe, 



A SYNOPSIS OF THE APHIDIDAE 53 

while the author feels that it is better associated with the Aphidini, 
inasmuch as the anteuual tubercles are very small and more or less 
indistinct and as the antennae are scarcely as long as the body. Van 
der Goot's genus, Myzaphis, has been accepted for the two species, 
Myzus rosarum (Walker) and Aphis ahietina Walker, and is included 
with the Aphidini. The species Aphis nymphaeae Linn., which Wil- 
son uses as the type of Rhopalosiphinn, has been taken from this genus 
and placed in Siphocorync, chiefly because of the apparent absence 
of antenna! tubercles and of the presence of distinct tubercles on the 
seventh abdominal segment. Therefore Aphis persioae Sulzer takes 
the place as type of the genus Rhopalosiphum. 

Key to California Genera 

1. Cornicles cylindrical, or at most but very slightly swollen on one side (figs. 

122, 152) 4 

— Cornicles distinctly swollen toward apex, or clavate (figs. 109, 113, 119) 2 

2. Antemial tubercles very large and tapering but not gibbous on the inner side ; 

the bases of the antennae being more or less approximate (fig. 107). 

Nectarosiphon Schouteden 

— Antennal tubercles distinct, but not large and tapering as above, being more 

or less toothed or gibbous on the inner side ; the bases of the antennae not 
approximate (figs. 108, 111) 3 

3. Antennal tubercles short and wedge-shaped, the outer side not evident (fig. 

108). Cauda ensiform and of medium size. Antennae at most but slightly 
longer than the body , Rhopalosiphum Koch 

— Antennal tubercles short, but not wedge-shaped (fig. 111). Antennae con- 

siderable longer than the body. Cauda very large and long. 

AmphoTophora Buckton 

4. Antennal tubercles large and as long on the outer as on the inner side (fig. 

106) 5 

— Antennal tubercles with outer side shorter than inner, or not evident (figs. 112, 

115, 116) 7 

5. Cornicles tapering, longer than cauda which is ensiform (fig. 152). Wing 

venation regular, with third discoidal twice-branched. 

Macrosiphum Passerini 

— Cornicles and cauda variable. Wing venation irregular and very striking with 

veins either wanting or combined, and shaded 6 

6. Antennal tubercles with short upper inner angle. Cauda shorter than cornicles 

and tapering. Stigmal and third discoidal veins meet in a broad dark 
band, giving the wing the appearance of having a closed triangular cell 
(fig. 110) Idlopterus Davis 

— Antennal tubercles with small rounded tubercle at the upper inner angle. 

Cornicles slightly constricted in the middle and at the tip. Wing venation 
variable, but usually the stigmal and third discoidal veins are partly 
joined and form a distinct, closed, four-sided cell Pentalonia Coquerel 

7. Antennal tubercles and first antennal segment with a strong tooth on the 

inner side of each (figs. 115, 116). Cauda short and tapering (fig. 118). 
Cornicles cylindrical and tapering slightly with tip outcurved (fig. 117). 

BhoTodon Passerini 



54 MISCELLANEOUS STUDIES 

— Autennal tubercles with a distinct but not prominent blunt projection forming 
the inner angle (tig. 112), but the prominent teeth as above are lacking. 
Cauda short, tapering, and usually triangular (fig. 121). Cornicles as 
above, being cylindrical, with a slight tapering from base to apex, and 
often slightly outcuryed at tip (fig. 122) Myzus Passerini 



21. Genus Amphorophora Buckton 

Buckton, Monog. Brit. Aphides, 187C. Type A. ampuUata n.sp. 
Key to Califobnian Species^ 

Cornicles pale, or at most slightly dusky, swollen and vasiform (fig. 113). VI 
spur longer than III, the latter with 35-45 sensoria rubi (Kalt.) 

Cornicles black, greatly dilated in apical one-half (fig. 161). VI spur shorter 
than III, latter with 13-17 sensoria latysiphon Davidson 

56. Amphorophora latysiphon Davidson 

Figure 161 

Davidson, Jour. Econ. Ent., vol. 5, p. 408, 1912 (orig. desc). 

Becords. — Vinca major, San Jose (Davidson) ; Courtland, Contra Costa County 
(Davidson); Stanford University, 1912 (Morrison, Essig). Convolvulus arvensis, 
San Jose (Davidson). Solanum tuherosum, Walnut Creek, Contra Costa County, 
igi.") (Davidson). 

This species has been found sparingly in the San Francisco Bay 
region on periwinkle, morning-glory, and potato tubers, although it 
has never seemed to be common. The author has not collected it, his 
only specimens being some taken by Essig on periwinkle near Stan- 
ford University. The odd shape of the cornicles is a distinguishing 
character. 

.57, Amphorophora rubi Kalt. 

Figures 111, 113, 162 

Kaltenbach, Monog. d. Pflanzenliiuse, p. 23, 1843. Aphis (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 5, p. 411, 1912 (list). 
Shinji, Can. Ent., vol. 49, p. 52, 1917 (list). 

Becords. — Bubics pan-ifiorus; San Jose (Davidson) : Buhus spp., Walnut Creek, 
1915 (Davidson) ; Berkeley (Shinji). 

This species has been taken a few times on thimble-berry in the 
San Francisco Bay region. Davidson writes that he has also found 
it on blaekberrv and loganberry in the vicinity of Walnut Creek, 



9G. 0. Shinji (Can. Ent., vol. 49, p. 51, 1917) described an aphid from CicuUa 
virosa var. calif ornica in Berkeley, which he called Amphorophora cicutae n.sp. 
The author has never seen specimens, so does not feel that he can recognize this 
as a good species. Of some half dozen new (?) species described by Shinji the 
author has found none, on examining specimens, that are good species, hence he 
cannot recognize this one at present. 



A SYNOPSIS OF THE APEIDIDAE 55 

Contra Costa County. The author has recently received specimens 
from Gillette of an alate viviparous female and apterous oviparous 
females taken in the vicinity of Fort Collins, Colorado. Inasmuch as 
the descriptions of this species are inadequate and not readily acces- 
sible it has been thouglit best to give here brief descriptions of the 
different forms. As no color notes were received with the specimens 
they must necessarilj' be omitted. 

Alate viviparous female (from Fort Collins, Colorado). — Antennae 
half as long again as the body, dusky, and placed on small but distinct 
tubercles. From the mounted material it appears as if III were 
dusky, IV, pale with extreme tip dusky; V, pale with apical one-third 
dusky; and VI dusky. VI spur is the longest segment, followed by 
III, IV, V, VI base, I, and II. The usual primarj' and accessory 
sensoria are present on VI base, and the primary sensorium on V. 
Secondary sensoria are present only on III. Thfese are small, circular, 
irregular-sized, and irregularly placed along the whole length of the 
segment. The number (35 to 40) is such as to make the segment 
appear tuberculate. The beak is quite large and long, reaching to or 
slightl.y bej'ond the third coxae. The thorax is dusky. The wings 
fairly large, and normal. The second branch of the third discoidal 
vein arises nearer to the base of the first branch than to the apex of 
the wing. Normally the measurements are as follows : From the base 
of the second branch of the third discoidal to the tip of the wing is 
about 0.8 mm., from the base of the first branch to the base of the 
second 0.4 mm., from the apex of the first branch to the apex of the 
second 0.29 mm. In one case the base of the second branch was 1.02 
mm. from the apex of the wing, and but 0.0-34 mm. from the base of 
the second, while the apices of the two branches were but 0.187 mm. 
apart. The legs are long, femora pale with apical one-fourth dusky, 
tibiae and tarsi du.sky. The abdomen is pale with some slight dorsal 
dark markings, these being indistinct in the mounted specimens. The 
cornicles are fairly long, clavate on the apical one-half or two-thirds, 
dusky throughout, and with the extreme tip reticulated. In length 
they are somewhat shorter than III, but longer than IV. The cauda 
is pale, short, and triangular, being about equal in length to the 
hind tarsi. 

Measurements : body length, 1.785 mm. ; antennae total, 2.788 mm. ; 
III, 0.68 mm. ; IV, 0.51 mm. ; V, 0.408 to 0.425 mm. ; VI, base, 0.12 
mm. ; VI, spur, 0.867 to 0.884 mm. ; cornicles, 0.578 to 0.646 mm. ; 
Cauda, 0.102 mm.; hind tarsi, 0.102 mm.; wing length, 3.128 mm.; 
width, 1.292 mm. ; expansion, 6.8 mm. 



56 MISCELLANEOUS STUDIES 

Apterous ovipurous female (Fort Collins, Colorado). — Pale 
throughout, with many small hairs scattered over the body. Most 
of these haii-s are simple, but some especially on the front of the head 
and on the bases of the antennae, are capitate. Antennae slightly 
longer than the body, pale, with VI and the apices of the other seg- 
ments dusky. VI spur and III are subequal or either one may be 
slightly longer than the other. These are followed by IV, V, VI base, 
I, and II. The usual primary and accessory sen.soria are present on 
VI base, and the primarj- sensorium of V. Secondary sensoria are 
present onlj- on III, and number about nine or ten. These are small, 
circular, but varying in size, and are arranged in a more or less 
even line along the basal one-half to two-thirds of the segment. Beak 
pale, with tip duskj', quite large and long, reaching to or beyond the 
third coxae. Thorax and legs normal, except the hind tibiae which 
are quite long, and' furnished with a large number of sensoria. 
These sensoria cover practically the whole joint. Cornicle very long 
and large, curved outward, pale, with apex dusky, and with distinct 
reticulations at the extreme tip. They are markedly larger than in 
the alate viviparous females, being considerably longer than the third 
antennal segment, and in some eases even half as long again. The 
Cauda is small, pale, and triangular, although somewhat larger in the 
viviparous female. 

Measurements : body length, 2.04 mm. ; width of thorax, 0.595 mm. ; 
antennae total, 2.446 mm. ; III, 0.646 to 0.697 mm. ; IV, 0.442 to 0.459 
mm. ; V, 0.356 to 0.374 mm. ; VI, base, 0.136 mm. ; VI, spur, 0.663 mm. ; 
cornicles, 0.918 to 0.952 mm. ; cauda, 0.187 mm. ; liiud tarsi, 0.136 mm. 



22. Genus Idiopterus Davis 

DavLs, Aun. Ent. Soe. Am., vol. 2, p. 198, 1909. Type, 7. neprelepidis n.sp. 

58. Idiopterus nephrelepidis Davis 

Figure 110 

Davis, Ann. Ent. Soc. Am., vol. 2, p. 198, 1909 (orig. tlesc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910 (list). 
Essig, Pom. Jour. Ent, vol. 3, p. 538, 1911 (list). 

Records. — Nephrolepis exaltata, Santa Paula (Essig), Palo Alto, April, 1915, 
San Diego, March to May, 1916; Riverside, February, 1917: Cyrtonium fulcotum, 
Berkeley, March, 1915 (Essig); ferns (unidentified species of house ferns), Stan- 
ford University (Davidson, Morrison); Viola sp., Claremont (Essig). 

This small black aphid is often found in houses and nurseries, and 
occasionally out of doors, on the fronds of various kinds of house 



A SYNOPSIS OF THE APHIDIDAE 57 

ferns, particularly the Boston fern. Essig has also found it on violets 
in the vicinity of Pomona College. The alate females have the wings 
beautifully marked with black and white. 

23. Genus Macrosiphum Passerini 
Passerini, Gli Afiili, 1860. Type Aphis rosac Linn. 
Key to California Species 
Alate viviparous females 

1. Cornicles slightly clavate on one side, somewhat as in Ehopalosiphum. 

tulipae (Monell) 

— Cornicles not clavate 2 

2. Ill as long as V and VI (base and spur) sonchella (Monell) 

— Ill not as long comparatively 3 

3. Ill pale, IV, V, and VI dusky jasminum (Clarke) 

— Not so ; if IV, V, and VI are dusky then III is also, except perhaps the base ; 

or if III is pale throughout then at least the greater part of IV and V are 
also pale 4 

4. VI (base and spur) shorter than III, but V and VI together are longer than 

III baccharadis (Clarke) 

— VI (base and spur) not shorter than III 5 

5. Secondary sensoria on III, IV, and V. Cornicles not reticulated. 

heucherae (Oestlund) 

— No secondary sensoria on V 6 

6. Secondary sensoria on both III and IV. Cornicles with tips at least reticulated 

(fig. 152) 7 

— No secondary sensoria on IV 10 

7. Cornicles and cauda subequal in length, the former being more or less bottle- 

shaped sanbomi Gillette 

— Cornicles longer than cauda 8 

8. Cauda light green. Secondary sensoria only occasionally present on IV and 

then very small and indistinct rosae (Linn.) 

• — Cauda dark (brown or black). Seven or more distinct secondary sensoria 
on IV 9 

9. Body with capitate setae, especially on head and antennae. 

artemisiae (Fonsc.) 

— Body without capitate setae. Abdomen with dark dorsal markings. 

lactucae (Kalt.) 

10. Cornicles with at least tips reticulated (fig. 132) 14 

— Cornicles with no reticulations (fig. 156) 11 

11. Body with fan-shaped setae artemlslcola (Williams) 

— Body without fan-shaped setae 12 

12. Distal two-thirds of cornicles black orthocarpus (Dvdn.) 

— Only tip of cornicles black 13 

13. Cornicles long and slender. About 18 secondary sensoria in a row on III 

(fig. 130) pisi (Kalt.) 

— Cornicles shorter and heavier. About 25 to 30 sensoria scattered irregularly 

along III (fig. 157) dirhodum (Walker) 

14. Cornicles with more than apical one-half reticiJate (fig. 149). 

ludovlcianae (Oestlund) 

— Cornicles with less than apical one-half reticulated (fig. 128) 15 



58 MISCELLANEOUS STUDIES 

15. Cornicles dusky for practically their entire length 20 

— Cornicles with less than apical one-half dusky 16 

16. Cornicles considerably longer than III, with apical portion curved outward. 

About a dozen, meilium-sized sensoria in a straight line along basal two- 
thirds of III (fig. 131) caUfomicum (Clarke) 

— Cornicles not considerably longer than III 17 

17. Cornicles and VI spur subequal, the former fairly long, slightly curved 

outward and slightly swollen before the tip (fig. 128) stanleyl Wilson 

— Cornicles considerably shorter than VI spur, and not swollen before the tip 18 

18. Secondary sensoria in a fairly straight line on III. Body not pulverulent 19 
- — Body covered with a slight pulveruleuce. Ill with about 30 fairly large- 
sized sensoria, more or less scattered along the entire length (fig. 143). 

albifrons Essig 

19. Cornicles about half the length of VI spur and considerably shorter than III, 

the latter with about 20 to 30 secondary sensoria pteridis Wilson 

— - Cornicles about two-thirds as long as VI spur and slightly shorter than III, 
the latter with about 15 sensoria (fig. 133) cucurbitae (Thomas) 

20. Ground or basal color of abdomen green 21 

— • Ground or basal color of abdomen red, brown, or black 2-!: 

21. Cornicles green, sometimes dusky at apex solanifoUi (Ashmead) 

— Cornicles black 22 

22. Ill with a small number (9-15) of secondary sensoria on basal one-half 

(fig. 135); longer than VI spur granarium (Kirby) 

— Ill with some 30 or more sensoria scattered along its entire length (figs. 151, 

159) ; subequal to or shorter than VI spur 23 

23. Cornicles and III subequal. Tibiae with apices only dusky rosae (Linn.) 

— Cornicles longer than III. Tibiae dusky throughout. 

rudbeckiae (Pitch) n.var. madia 

24. Cauda pale 25 

— Cauda dusky 27 

25. Ill and VI spur subequal rosae (Linn.) 

— • III shorter than VI spur 26 

26. Cauda about one-half as long as cornicles, the latter shorter than IV. 

chrysanthemi (Oestlund) 

— Cauda slightly more than one-half as long as cornicles, the latter equal to or 

longer than IV rudbeckiae (Fitch) 

27. Ill and VI spur subequal 28 

— Ill longer than VI spur taraxici (Kalt.) 

28. Body yellowish-brown in color; legs same except tarsi and tips of tibiae and 

femora which are dusky to black Valerianae (Clarke) 

— ■ Body dark reddish-brown to black in color; legs dusky throughout. 

ambrosiae (Tliomas) 

Apterous viviparotis /fnioJesio 
1. Cornicles clavate on one side, somewhat as in Bltopalosiphnm. 

tulipae (Monell) 
— • Cornicles not so, being cylindrical or subcylindrical 2 

10 Only the species of which there are specimens available to the author, or of 
which there are adequate descriptions, are included in this key. The species rep- 
resented in the author's collection are marked with an asterisk (*). The author 
recognizes the great difficulty in separating the apterae of various species, par- 
ticularly in this genus, and offers this key merely as a slight aid toward the recog- 
nition of the better known species. 



A SYNOPSIS OF THE APHIDIDAE 59 

2. Ill without or at moet with only a few secondary sensoria (0-12) 11 

— Ill with several (over 12) secondary sensoria scattered along the greater part 

of its length 3 

3. Cornicles short and tapering, being somewhat bottle-shaped and not distinctly 

longer than the Cauda sanboml Gillette* 

— Cornicles normal, being cylindrical and considerably longer than tlie Cauda 4 

4. Ill and IV with secondary sensoria heucherae (Oestlund) 

— IV without secondary sensoria 5 

5. General body color dark, being red, wine, brown or black 6 

— General color lighter, usually being a shade of green 8 

6. Cauda black. Legs black, except the bases of the femora taraxlci (Kalt.) 

— Cauda pale. Legs with at least the bases of the femora and tibiae not black 7 

7. Legs green, except tarsi and apices of femora and tibiae. Cauda not more than 

half the length of the cornicles. Not more than ten to twelve sensoria on 

the basal one-third of III rosae (Linn.)* 

— • Legs black, except bases of femora and tibiae, which are light brown. Cauda 
more than half the length of the cornicles. A considerable number of 
sensoria scattered over more than the basal one-half of III. 

nidbeckiae (Fitch)* 

8. Cornicles subequal to or shorter than III. Body covered with a whitish pul- 

verulence 9 

— Cornicles distinctly longer than III. Body without whitish pulverulence .... 10 

9. Cornicles, except tip, and Cauda green; the former subequal in length to III 

and about twice as long as cauda albifrons Essig* 

— Cornicles black, cauda yellow or light brown; the former considerably shorter 

than III and not twice as long as cauda ludovicianae (Oestlund)* 

10. Cauda quite broad and blunt at end. Cornicles with not more than apical one- 

sixth reticulated rosae (Linn.) * 

— • Cauda slender and pointed. Cornicles with apical one-fourth reticulated. 

rudbeckiae (Fitch) n.var. madia* 

11. Body covered with capitate or fan-shaped setae 12 

— Body without specialized setae 14 

12. Setae with fan-shaped tips and thickly covering the body. Cornicles slender 

and imbricated for their entire length arte'misicola (Williams)* 

— Setae capitate and only sparsely covering body 13 

13. Cornicles fairly stout, with tips reticulated, and about twice as long as cauda. 

artemisiae (Fonsc.) 

— Cornicles slender, with no reticulations, and considerably more than twice the 

length of the cauda pteridis Wilson 

14. Cornicles with tips at least reticulated 16 

— Cornicles with no reticulations 15 

15. Cornicles very long and slender. Antennae considerably longer than body. 

pisi (Kalt.)* 

— Cornicles shorter and heavier. Antennae at most but slightly longer than 

body dirhodum (Walker)* 

16. Cornicles for the most part dusky or black 17 

— Cornicles mostly pale or green 19 

17. Cornicles and III subequal. Body not pulverulent 18 

— Cornicles considerably shorter than III. Body more or less pulverulent. 

ludovicianae (Oestlund)* 



60 MISCELLANEOUS STUDIES 

18. Ill with but two or four sensoria near base; longer than VI spur. 

granarium (Kirby)* 

— Ill with six or so sensoria on basal one-half; shorter than or equal to VI 

spur rosae (Linn.)* 

19. Cornicles longer tlian III 20 

— Cornicles at most subequal to III 21 

20. Antennae pale, except VI and the apices of III to V. Cornicles slightly 

swollen near distal end Stanley! Wilson* 

— • Antennae dusky, except III, basal part of IV, and perhaps the extreme base 
of V. Cornicles long, slender, and out-curved caUfornicum (Clarke)* 

21. Cauda broad, and blunt, with the sides almost parallel and about half as long 

as cornicles lactucae (Kalt.) * 

— Cauda slender-pointed, and more than half as long as cauda 22 

22. VI spur and III subequal solanifoUi (Ashmead)* 

— VI spur considerably longer than III ., cucurbitae (Thomas)* 



59. Macrosiphum albifrons Essi<j 

Figures 143, 144 

Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909. Macrosiphum sp. (list). 
Essig, Pom. Jour. Ent., vol. 3, p. 543, 1911 (orig. desc). 

Mecords. — Lupinus sp., Santa Paula (Essig) ; Stanford University (Davidson) ; 
Jasper Eidge, Coast Range Mountains, Santa Clara County, April, 1912 (V. G. 
Stevens) ; Berkeley, April, 1915 (Geo. Shinji) ; Mount Hood, Oregon, August, 
1916 (E. A. McGregor). 

This large, flocculent aphid is found occasionally infesting various 
lupines tliroughout the Pacific Coast, from southern California north, 
well into Oregon. The author has specimens from Berkeley and 
Oregon, although he has never collected it himself. 



60. Macrosiphum ambrosiae (Thomas)? 

Thomas, 111. Lab. Nat. Hist., Bull. 2, p. 4, 1878. Siphonophora (orig. 

desc.). 
Sanborn, Kans. Univ. Sci., Bull. 3, p. 74, 1904 (desc). 

Records. — Eelianthus annum; Orange (T. D. A. Cockerell) ; San Diego, April, 
1916. 

In 1915 the author received a few specimens of this species from 
T. D. A. Coclserell from Orange, and in 1916 he collected it once on 
sunflower in Exposition Park, San Diego. At first it was thought to 
be M. sonchi (Linn.), and was so reported by Cockerell. Since then 
it was identified by J. J. Davis as probably M. anibrosiae (Thomas). 



A STNOPSIS OF THE APEIDIDAE 61 

61. Macrosiphum artemisiae (Fonsc.) 
Figures 142, 145 

Boyer de Fonseolnibe, Ann. Ent. Soc. France, vol. 10, p. 162, 1841. Aphis 

(orig. dcsc). 
Essig, Pom. Jour. Ent., vol. 3, p. 54(i, 1911. Macrosiphum frigidae (Oest.) 

(desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 133, 1914. Macrosiphum frigidae 

(Oest.) (list). 
Wilson, Trans. Amer, Ent. Soc, vol. 41, p. 97, 1915 (desc). 

Records. — Artemisi-a californica; Santa Paula (Essig) ; Walnut Creek, Contra 
Costa County (Davidson). 

Occasioiuilly tliis species is foiiiul infesting the tender shoots of 
the common California sage brusli. It is characterized by the presence 
of capitate hairs scattered sparsely over the body, particularly of the 
apterous female. The .s.ynonomy above is after Wilson, who lists 
M. frigidae (Oestlund) as a synonym of artemisiae (Fonsc). 

62. Macrosiphum artemisicola (Williams) 

Figures 146, 147 

Williams, Univ. Neb. Studies, vol. 10, p. 73, 1910. Siphonophora (orig. 
desc. ) . 
• Wilson, Trans. Am. Ent. Soc, vol. 41, p. 96, 1915 (desc). 

Records. — Artemisia tridentata, A. vulgaris; Oregon (California) (Wilson). 

Although there is no published record of the presence of this 
species in California it is included here on Wilson's authority. He 
stated to the author that he had found it in California, although he 
failed to give any date or locality record. This is characterized bj' 
the fan-shaped setae which thickly cover the body of the apterae, and 
which are present on the ventral side of the abdomen of the alates. 
The author has specimens taken by R. W. Haegele in the sum.mer of 
1915 on Arlemi.sia sp. near Canton, Montana. 

63. Macrosiphum baccharadis (Clarke) 
Clarke, Can. Ent., vol. 35, p. 254, 1903. Neetarophora (orig. desc). 
Record. — Baccharis sp., Berkeley (Clarke). 

This species is one of those desci'ibed by Clarke, but since then 
unknown. It is possible that it is M. ritdbeckiae (Fitch), which is so 
common on Baccharis throughout California. 



62 MISCELLANEOUS STUDIES 



64. Macrosiphum calif ornicum (Clarke) 

Figures 131, 132 

Clarke, Can. Ent., vol. 35, p. 2.54, 1903. Nectarophora (orig. dese. apterae). 
Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909 (list). 
Daridson, Jour. Eeon. Ent., vol. 3, p. 380, 1910 (list). 
Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911 (list). 

Essig, Pom. Jour. Ent., vol. 3, p. 548, 1911. M. laevigatae, n.sp. (orig. 
desc). 

Records. — Salix sp. ; Newcastle, Placer County (Clarke); Stanford University 
and Penryn, Placer County (Davidson) ; Stanford University, November, 1914 
(Morrison), May, 1915; Berkeley, April, 1915 (Shinji); August, 1915, Salix 
laevigata; Santa Paula (Essig) ; Riverside, May, 1917. 

Clarke described the apterous females of a species of Nectarophora 
(Macrosiphum) from specimens taken on willow in Placer Connty. 
Becanse of the extremely long cornicles it is possible to identify this 
with specimens taken since throughout the San Francisco Bay region 
on various species of willows. Essig 's M. laevigatae from Santa 
Paula is the same species, having been compared by the author with 
specimens from Stanford University and Berkeley. Morrison has 
taken the males and oviparous females of this species in the vicinity 
of Stanford University in November, 1914. The author has reared 
specimens of Aphidius polygonaphis Fitch, and Prnon sinudans Prov. 
from tills species taken in Berkeley. 



65. Macrosiphum chrysanthemi (Oest.) 

Oestlund, 14th Eep. Geol. Surv. Minn., vol. 22, 1886. Siphonophora (orig. 

desc). 

Davidson, Jour. Econ. Ent., vol. 5, p. 411, 1912 (list). 

Record. — Undetermined species of Compositae ; Courtland (Davidson). 

This is a doubtful species taken by Davidson at one time from an 
undetermined compo.site near Courtland. The author is entirely 
unacquainted with the species. 



66. Macrosiphum cucurbitae (Tlios.) 

Figures 133, 134 

Thomas, 8th Ann. Rep. Illinois St. Ent., p. 66, 1879. Sip}ionophora (orig. 
desc. ) . 

Record. — Cucuriita sp., Hayward, Alameda County, July, 1915 (Roy E. Camp- 
bell) ; Los Angeles, May, 1917. 



A SYNOPSIS OF THE APHIBIDAE 63 

In July, 1915, Roy E. Campbell of the Bureau of Entomology, 
sent the author specimens of a Macrosiphum sp. from squash in Hay- 
ward. In 1917 the autlior found the same species abundantly on 
squash in Los Angeles. These the author identified as being specimens 
of 31. cucurbifae (Thomas). Later J. J. Davis verified the deter- 
mination. This is a new record for California. As the available 
descriptions of this species are quite inadequate, tlie author gives 
herewith a few descriptive notes taken from these specimens. 

Alate viviparous feviale. — Antennae longer than the body, placed 
on distinct frontal tubercles, dusky except I, II, and extreme base 
of III. The spur of VI is the longest segment, followed by III, which 
is about four-fiftlis as long. IV and V are subequal, and almost as 
long as III. Tlie usual primary and accessory sensoria are present 
on V and VI. Secondary sensoria are present on III (fig. 133), being 
small, circular, numbering about 14 to 15, and arranged in a fairly 
even row along the whole length of the segment. Beak pale with 
dusky tip, reaching to tlie second coxae. Thorax and abdomen green, 
the thoracic lobes not conspicuously darkened. Cornicles (fig. 134) 
green with apical one-third dusky, equal to or slightly longer than 
III, imbricated with tip reticulated. Cauda large, pale, vasiform, 
slightly more than half the length of the cornicles, reaching to their 
apices. Wings and legs normal. 

Measurements : Body length, 2.3 mm. ; antennae total, 3.25 to 3.35 
mm. ; III, 0.685 to 0.714 mm. ; IV, 0.629 to 0.646 mm. ; V, 0.603 to 
0.612 mm. ; VI, base, 0.136 to 0.153 mm. ; VI, spur, 0.935 to 0.696 mm. ; 
cornicles, 0.714 to 0.731 mm. ; cauda, 0.408 mm. 



67. Macrosiphum dirhodum ("Walker) 

Figures 156, 157 

Walker, Ann. Nat. Hist., (2), vol. 3, p. 43, 1848. Aphis (orig. desc). 
Theobald, Jour. Econ. Biol., vol. 8, p. 128, 1913 (desc.). 
Patch, Maine Agr. Exp. Sta., Bull. 233, p. 268, 1914 (note). 
Gillette, Jour. Econ. Ent., vol. 8, p. 103, 1915 (note). 

Record. — Rose, Santa Ysabel (3000 feet altitude), San Diego County, May, 
1916; Riverside, April, 1917. 

The author found this species sparingly on rose near Santa Ysabel, 
San Diego County, in May, 1916, and again in April, 1917, in River- 
side. According to Gillette, this species passes the winter on rose, 
and the summer on various grains and grasses, as M. rosac (Linn.) 



64 MISCELLANEOUS STUDIES 

may do. These are the only records of it in California. The author 
has compared it with specimens taken by R. W. Doane in 1915 on 
grain in Utah. 



68. Macrosiphum granarium (Kirby) 

Figures 135, 148 

Kirby, Linn. Soc. Trans., vol. 4, p. 238, Aphis (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 5, p. 411, 1912 (list). 
Theobald, Jour. Econ. Biol., vol. 8, p. 58, 1913 (desc). 
Davidson, Mon. Bull., Cal. Comm. Hort., vol. 6, p. 65, 1917 (note). 

Mecords. — Graminaceae (various species) ; San Jose (Davidson) ; Stanford 
University, January to May, 1915; Berkeley, March, 1915: Typha latifolia 
(Davidson). 

This is a more or less common species of Macrosiphum on various 
grains and grasses in the San Francisco Bay region during the winter 
and spring. In late spring and earlj' summer, as the grasses begin 
to dry out, it leaves them for the cat-tail rush or California tule 
(Davidson, 1917). In the late fall or early winter it returns to the 
grains and grasses, where it passes the winter in the viviparous forms. 



69. Macrosiphum heucherae (Thomas) 

Thomas, 8th Ann. Rep. Illinois St. Eut., p. 66, 1879. Siphonophora (orig. 

desc). 
Davidson, Jour. Econ. Ent., vol. 8, p. 427, 1915 (desc). 

Record. — Heuchera hartwegi, Eedwood Canyon, Contra Costa County (David- 
son). 

In the latter part of May, 1914, Davidson found all the forms, 
including the apterous and alate viviparous females, the apterous 
oviparous females, the alate males, and eggs on the flower stalks of 
alum root in Contra Co.sta County. Since his description no record 
has been made concerning the species. The author is unacquainted 
with it, having never seen specimens. 

70. Macrosiphum jasmini (Clarke) 
Clarke, Can. Ent., vol. 35, p. 252, 1903. Nectarophora (orig. desc). 
Secord. — Jessamine, Berkeley (Clarke). 

Since Clarke's description of the apterous viviparous females of 
this species it has never been found. Its identity is, therefore, un- 
known to the author. 



A SYNOPSIS OF THE APHIDIDAE 65 



71. Macrosiphum lactucae (Kalt.) 

Kaltenbach, Monog. J. Pflanzenlause, p. 199, 1857. Ncctarophora (orig. 

desc). 
Sanderson, Can. Ent., vol. 33, p. 69, 1901. Ncctarophora (desc). 
Essig, Univ. Calif. Publ., Entom., vol. 1, p. 328, 1917 (list). 

Secord. — Cicorium intijhus, Rutherford, Napa County, 1916 (Essig). 

This species has been taken only by Essig on chicory in Napa 
County during June, 1916. As its detei-mination is doubtful the 
autlior gives herewith a brief description of the alate female. 

Body pale to green, with the following parts more or less dusky : 
head, antennae, prothorax, thoracic lobes, apex of beak, tarsi, apical 
one-fifth to one-fourth tibiae, apical one-half femora, cornicles, anal 
plate, marginal spots on the abdominal segments, submarginal spots 
of the second and third abdominal segments, dorsal bands on the 
fourth and fifth, and the dorsum of the remaining abdominal seg- 
ments. Eyes red. 

The antennal tubercles are prominent and project rectangularly 
inward. A prominent frontal tubercle is present on the apex. The 
antennae are about half as long again as the body. The usual primary 
and accessor}- sensoria are present. On III there are from thirty-five 
to forty-five circular secondarj- sensoria ; on IV fi'om five to fifteen 
secondary sensoria. These two segments appear tubereulate. The 
beak reaches beyond the second coxae. The cornicles are longer than 
the Cauda, and subequal in length to the fourth antennal segment. 
They are subcylindrical and fairly stout. The cauda is long and ensi- 
form, reaching to the tip of the cornicles. The wings and venation 
are normal. 

Measurements (of three specimens) : Body length, 1.836 to 1.955 
mm. ; width of thorax, 0.765 to 0.833 mm. ; antennae, total, 2.805 to 
2.992 mm. ; III, 0.680 to 0.697 mm. ; IV, 0.441 to 0.527 mm. ; V, 0.391 
to 0.425 mm. ; VI, base 0.085 to 0.119 mm. ; VI, spur 0.952 to 1.105 
mm. ; cornicles, 0.441 to 0.493 mm. ; cauda, 0.238 to 0.272 mm. ; hind 
tarsi, 0.136 to 0.153 mm. ; wing, length, 3.145 to 3.315 mm. ; width, 
0.952 to 1.139 mm. ; expansion, 7.36 to 7.87 mm. 

72. Macrosiphum ludovicianae (Oestund) 

Figures 136, 148 

Oestlund, Minn. Geol. Nat. Hist. Surv., vol. 14, p. 23, 1886. Siplwnopliora 

(orig. desc.). 
Davidson, Jour. Econ. Ent., vol. 7, p. 136, 1914 (list). 
Wilson, Trans. Am. Ent. Soc, vol. 12, p. 98, 101.5 (desc). 



66 MISCELLANEOUS STUDIES 

Becords. — Artemisia hcterophylla ; Walnut Creek, Contra Costa County (David- 
son), Berkeley, 1915 (Shinji) ; Artemisia dracunculoides, Convolvulus sp., Stachys 
bullata, Berkeley, 1915 (Shinji). 

This species is quite common in tlie San Francisco Bay region on 
various species of sagebrush. George Shinji has taken it also on hedge- 
nettle and bindweed in Berkeley. It is distinguished from other sage- 
infesting species of Macrosiphwnt by the fact that the body of the 
apterous females is covered with pointed setae as opposed to the fan- 
shaped setae of M. artemisicola (Williams), and the capitate setae 
of M. artemisiae (Fonsc). 



73. Macrosiphum orthocarpus Davidson 

Davidson, Jour. Econ. Ent, vol. 2, p. 304, 1909 (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910 (list). 

'Record. — Orthocarpus purpurascens ; Stanford University (Davidson). 

Since Davidson found the specimens on owl-clover from whicli he 
described this species, it has not again been taken. 



7-t. Macrosiphum pisi (Kalt.) 

Figures 130, 150 

Kaltenbach, Monog. d. Pflanzenlausc, p. 23, 1843. Aphis (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909 (Ust). 
Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910 (list). 
Essig, Pom. Jour. Ent., vol. 2, p. 336, 1910. Nectarophora (desc). 
Branigan, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 285, 1915. M. destruc- 
tor (Johnson) (list). 
Davis, V. S. Dept. Agr., Bull. 276, p. 11, 1915 (list). 

Records. — Pisum sativum.; Clareniont, Santa Ana, and Ventura (Essig) ; Ala- 
meda County (Brannigan) ; El Cajon, San Diego County, May, 1916: Lathyrus 
odoratus; Stanford University (Davidson, Morrison); San Diego, October, 1916: 
Viola sp.; Claremont, Santa Ana, Ventura (Essig); Medicago sp. ; Holtville, 
Imperial County (V. L. Wildermuth) : Psorales macrostachya ; Santa Paula 
' (Essig). 

Tlie pea aphis is quite common throughout the state, especially on 
garden and sweet peas. It has been taken a few times on other plants, 
such as alfalfa, violets, and leather-root, but it is uncommon. This 
species is readily distinguished by its bright, shining green color, large 
size, and long, slender, imbricated, but non-reticulated cornicles. 



A SYNOPSIS OF THE APBIDIDAE 67 



75. Macrosiphum pteridis Wilson 

Figures 317, 318 

Wilson, Trans. Am. Ent. Soe., vol. 41, p. 101, 1915 (orig. desc). 

Records. — Pieris aquilina; Walnut Creek, Contra Costa County, 1915 (David- 
son). 

This species has been found by Davidson on the fronds of common 
brake in the San Francisco Baj' region. Wilson reported it as present 
throughout southern and western Oregon. There are a few specimens 
of the alate females in the author's collection, received from Davidson. 



76. Macrosiphum rosae (Linn.) 

Figures lOli, 151, 152 

Linnaeus, Syst. Nat. vol. 4, p. 73, 1735. Aphis (orig. desc.). 

Clarke, Can. Ent., vol. 35, p. 254, 1903. Nectarophora (list). 

Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909 (list). 

Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910 (list). 

Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911 (list). 

Essig, Pom. Jour. Ent., vol. 5, p. 550, 1911 (desc). 

Carnes, Mon. Bull. Cal. Coram. Hort, vol. 1, p. 398, 1912 (list). 

Hecords. — Rose; through California from Humboldt County south to San Diego 
County (Clarke, Davidson, Morrison, Essig, Ferris, Shinji, the author). 

This is the common pink and green aphid of roses, known the 
world over. The apterae are found most abundantly in the late win- 
ter and early spring on the buds and stems of rose. As the alates are 
matured they fly away, supposedly either to other rose bushes or to 
various grains and grasses. This past spring (1917) it has been very 
abundant in the vicinity of Riverside, but the previous spring (1916) 
in San Diego it was rare. There the most abundant rose aphis was 
Myzaphis rosarum (Walker). 

77. Macrosiphum rudbeckiae (Fitch) 

Fitch, Cat. Homop. N. Y., p. 66, 1851. Aphis (orig. desc). 
Essig, Pom. Jour. Ent, vol. 3, p. 400, 1911. Aphis (desc)." 
Davidson, Jour. Econ. Ent., vol. 7, p. 137, 1914 (list). 

Records. — Ambrosia psilostachya ; Santa Paula (Essig) ; Bacchuris vimin-alis; 
Santa Paula (Essig), Riverside, September, 1916; Dipsacus fullonum; San Jose 
(Davidson): Helianthus aiinuus ; Riverside, September, 1916; SaUx sp. ; Chrysan- 
themum; Arlington, Riverside County, September, 1916; undetermined species of 
Compositae ; Redwood Canyon, Contra Costa County, July, 1914 (R. W. Haegele). 



11 In the drawings accompanying this description by Essig the following mis- 
takes are noticeable: the third discoidal vein of the forewings is twice-branched 
instead of once-branched, and the third antenal segment of the apterous female 
bears several secondary sensoria instead of none, as figured. 



68 MISCELLANEOUS STUDIES 

Tliis reddish-eolored Macrosiphum is distributed abundantly 
through the San Francisco Baj' region and southern California on 
various Compositae. In one ease the author found it doing consider- 
able damage to ehr^-santhemums by stunting and distorting the buds. 
Once he found it infesting the tender leaves and stalks of willow. 
The author reared specimens of Diarctus rapae Curt, from an infesta- 
tion of this species taken on willow. 

77a. Macrosiphum rudbeckiae (Pitch) var. madia n.var. 

Figures 153, 154 

In September, 1915, the author found a species of Macrosiphum 
infesting the heads of tarweed {Madia sativa) on the campus of the 
University of California, Berkeley. Specimens of Praon simiilans 
Prao. were reared from this collection. Mounted specimens are almost 
identical with .V. rudbeckiae (Fitch), but in life they differ in the 
coloration. Because of this it has been thought best to describe it 
herewith as a color variety of M. rudheckiae, naming the variety. 
madia, after its host plant. 

Host: Madia sativa. Date: Septcmlier 12, 1915. 

Locality: Berkelej', California. Collection number: AFS 70-15. 

Alate viiuparous female. — Prevailing color: dark-green, slightly 
pruinose. Head brownish (fuscous), about as long as broad, with 
distinct antennal tubercles. Antennae black, except I and II and the 
base of III, which are concolorous with the head. The spur is slightly 
longer than III; IV is next in length, followed by V, VI, and I, which 
are subequal, and II, which is the shortest segment. The spur is about 
six times as long as the baise of VI. The usual primary sensoria are 
present on V and VI, and the usual aeces.sory sensoria on VI. IV is 
without sensoria, III has 25-35 irregularly arranged, various-sized 
secondary sensoria placed along the whole length of the segment 
(fig. 154). The thorax is fuseous; the prothorax with rather distinct 
lateral tubercles. The beak is slightly dusky with the apical one-third 
lilaek, reaching to the second coxae. The abdomen is greenish with a 
slight pulveralence, making it appear pruinose. The cornicles are 
long, slightly tapering, black except the ba-sal one-third, which is 
concolorous with the abdomen, apical one-fifth reticulate (fig. 153). 
The Cauda is long and pointed, pale (slightly reddish?), about one- 
half as long as the cornicles. The legs are black except the basal half 
of the femora and the coxae, which are greenish. The wings and 
venation are normal. 



A SYNOPSIS OF THE APHIDIDAE 69 

Measurcmtiits : Body length (exclusive of cauda), 2.11 mm.; width 
of thorax, 0.91 mm. Antennae : total, 2.07 mm. ; I, 0.12 mm. ; II, 
0.09 mm. ; III, 0.76 mm. ; IV, 0.55 mm. ; V, 0.47 mm. ; VI, 0.12 mm. ; 
sjiur. 0.78 mm. ; cornicles, 0.91 mm. ; eauda, 0.45 mm. ; beak, 0.89 mm. ; 
hind tarsns, 0.14 mm. Wing: length, 3.6 mm.; width, 1.25 mm.; 
expansion, 8.11 mm. 



78. Macrosiphum sanborni Gillette 

Figures 1-11, 1S3 

Sanborn, Ivans. Univ., Sci. Bull. 3, p. 73, 190-1. Macrosiphum chrysaiUhemi 

(dese. ala. vivi.). 
Gillette, Can. Eut., vol. 11, p. 65, 1908 (orig. desc. apt. vivi.). 

Secords. — Chrysanthemum; Stanford University, May, 1915; Riverside, March, 
1917. 

Twice has the author found this species: once a small infestation 
in the greenhouse of Stanford University, and once abundantly out 
of doors in Riverside. It is an interesting species in that it does not 
fit well into any known genus. Except for the cornicles it fits Macro- 
siphum. and has been so considered. The cornicles are, however, short, 
being searcelj' longer than the cauda, and are somewhat bottle-shaped, 
being considerably smaller at tlie apex than at the base. 



79. Macrosiphum solanifolii (Ashmead) 

Figures 137-140, 159-160 

Ashmead, Can. Ent., vol. 12, p. 91, 1881. Siphonophora (orig. desc). 

Clarke, Can. Ent., %'ol. 35, p. 252, 1903. Nectarophora citrifolii (Ashmead) 
(list). 

Davidson, Jour. Econ. Ent., vol. 31, p. 380, 1910. Macrosiphum citrifolii 
(Ashmead) (list). 

Essig, Pom. Jour. Ent., vol. 3, p. 592, 1911. Macrosiphum citrifolii (Ash- 
mead) (desc). 

Davidson, Jour. Econ. Ent, vol. 5, p. 411, 1912 (list). 

Patch, Maine Agr. Exp. Sta., Bull. 242, 1915 (desc). 

Records. — Citrus sp.; Azusa, Los Angeles County (Clarke); Lindsey, Tulare 
County (Clarke) ; Santa Paula (Essig) ; Disporum hookeri; Berkeley, May, 1915 
(Shinji) : Solanum nigrum; Stanford University, October, 1916 (Ferris) : Fuchsia 
sp. ; Berkeley, July, 1915: Sonclius asper and S. oleraceus; Stanford University, 
February, 1915: apple; Stanford University, May, 1915; El Cajou, San Diego 
County, July, 1916: Atriplcx sp.; Berkeley, September, 1915: Oxalis corniculata, 
Biverside, February, 1917: Deinandra fasciculaia. Riverside, February, 1917: 
Erodium moschatum; Pasadena, April, 1917 (R. E. Campbell); Riverside, April, 
1917. 



70 MISCELLANEOUS STUDIES 

This "piuk and green aphid of potato" is distributed throughout 
California on a large varietj- of plants. It is recognizable bj' the long 
reticulated cornicles and black antennae. When the author first exam- 
ined specimens of Macrosiphum citrifolii (Ashmead) in Essig's collec- 
tion he was struck with its resemblance to this species. In fact, after 
considerable study he could not find any constant differences. This was 
in 1915 in Berkeley. This past spring (1917) he had the opportunity 
in Riverside of making some transfer tests with specimens from oxalis. 
Migrants wei-e placed under muslin bags on sucker growth of orange. 
It was observed that these settled there readily and produced young, 
demonstrating that the citrus species is the same as the other. On 
the strength of this Macrosiphum citrifolii (Ashmead) is listed as a 
synonym of this species. 



80. Macrosiphum sonchella (Monell) ? 

Monell, TJ. S. Geol. Geog. Surv., Bull. 5, p. 21, 1879. Siplionophora (orig. 

desc). 
Clarke, Can. Ent., vol. 35, p. 252, 1903. Nectarophora (list). 
Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909 (list). 
Davidson, Jour. Econ. Ent., vol. 2, p. 380, 1910 (list). 

Rccurcls. — Sonchus sp.; Berkeley, Newcastle, and Palo Alto (Clarke); Stan- 
ford University (Davidson). 

According to Jlorrison the species listed as this by Davidson is 
not Macrosiphum sonchella (Monell), although he cannot say what 
it is. Consequently Clarke probably referred to the same specires as 
did Davidson. As the author has never seen specimens he can make 
no statement as to its identity, so lists it as it has been heretofore. 



81. Macrosiphum stanleyi Wilson 

Figures 128, 158 
Wilson, Troe. Ent. Soc. Brit. Columbia, January, 1915 (orig. desc.). 
Record. — Samhitcvs callicarpa californica; Berkeley, June, 1915. 

From the early part of June, 1915, until the middle of August, 
this species was very abundant on an elderberry tree in the Botanical 
Gardens of the University of California. By the latter part of August 
all specimens had disappeared. Since then the author has never seen 
the species. J. J. Davis kindly identified these specimens. 



A SYNOPSIS OF THE APHIDIDAE 71 



82. Macrosiphum taraxici (Kalt.) 

Kalteubacli, Moiiog. d. Pflanzenliiuse, p. 30, 1743. Aphis (orig. desc). 
Theobald, Jour. Econ. Bio!., vol. 7, p. 77, 1913 (desc). 

Eecord, — Taraxacum officinale; California (Wilson). 

H. F. Wilson stated to the author that he liacl taken this species 
on dandelion (Taraxacum officinale) in California, although he gave 
no date or locality record. 

83. Macrosiphum tulipae (Monell) 

Monell, IT. S. Geol. Geog. Surv., Bull. 5, p. 19, 1879. Siphoiwphora (orig. 

desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910 (list). 

Eecords. — Tulipa sp. ; Stanford University (Davidson); Liriodendroii sp. ; 
Berkeley, 1915 (Essig, Shinji). 

This species is not known to the author. It has been found on 
tulips and on the tulip trees in the San Francisco Bay region by 
Davidson, Essig, and Shinji. 

84. Macrosiphum Valerianae (Clarke) 

Clarke, Can. Ent., vol. 35, p. 253, 1903. Nectaropliora (orig. desc). 
Eecord. — Valeriana officinialis; Berkeley (Clarke). 

In 1903 Clarke described this species from specimens taken on 
heliotrope in Berkeley. Since then it has not again been found. 

24. Genus Myzus Passerini 
Passerini, Gli Afidi, 1860. Type Aphis rihes Linnaeus. 
This genus is very closely related to Rhopalos-iphuni Koch, the 
principal difference being in the shape of the cornicles. However, 
some species fall easily into one or the other genus, depending entirelj' 
upon what form one has. In this respect Rhopalosiphum pcrsicae 
(Sulz.) is particularly noticeable, the spring migrants having the 
clavate cornicles of Rhopalosiphum, the fall migrants having the 
cylindrical cornicles of Myzus. The author has followed Van der 
Goot in taking out of this genus M. rosarum (Walker) and placing it 
in the genus Myzaphis v.d.G. The antennal tubercles are lacking, 
thus placing the species in the Aphidini instead of the Macrosiphini. 
There are at present ten species of Myzus known to occur in Califor- 
nia. Following is a key to them : 



72 MISCELLANEOUS STUDIES 

Key to the California Species 
Alate viviparous females 

1. Seeonilary sensoria present on III only 5 

— Secondary sensoria present on other segments as well as on III 2 

2. Secondary sensoria on III, IV, and V S 

— Secondary sensoria on III and IV, none on V fragaefolii Cockerell 

3. Cornicles dusky for entire length cyiiosbati (Oestlund) 

— • Cornicles mostly pale 1 

4. Thoracic lobes distinctly darker than general body color, being black or dark 

brown aquilegia Essig 

— Thoracic lobes at most only slightly darker than body, being a pale brown. 

braggii Gillette 

5. Body black throughout cerasi (Fabricius) 

— Body not black throughout 6 

6. Cornicles pale except at extreme tip 7 

— Cornicles with more than tip dusky 8 

7. VI spur longer than III, the latter with but 9 to 12 sensoria. 

varians Davidson 

— VI spur at most equal to III, the latter with 18 to 26 sensoria. 

lycopersici (Clarke) 

8. Cornicles longer than either IV or V 10 

— Cornicles not longer than either IV or V 9 

9. VI spur longer than II circumflexum (Buckton) 

— VI spur shorter than III ribifolii Davidson 

10. Ill with 15 to 25 sensoria (fig. 178) rhamni (Fonsc.) 

— Ill with but 9 to 12 sensoria varians Davidson 

Apterous viviparotis femiile 

1. Body covered with capitate hairs 2 

— Body not covered with capitate hairs except on head and antennae 5 

2. Secondary sensoria on III 3 

— No secondary sensoria on III 4 

3. Cornicles dusky ribifolii Davidson 

— Cornicles pale except tip aqtuilegiae Essig 

4. Cornicles almost twice as long as III. Body fairly large sized. 

braggii Gillette 
— ■ Cornicles but slightly longer than III. Body small sized. 

fragaefolii Cockerell 

5. Secondary sensoria on III 6 

— No secondary sensoria on III 7 

6. VI spur longer than III. Several sensoria scattered along the whole length 

of III cynosbati (Oestlund ) 

— VI spur at most equal to HI. Only a few (1-3) sensoria at base of III. 

lycopersici (Clarke) 

7. Ill longer than cornicles. Dorsum of abdomen with dusky ninrkings, shaped 

somewhat as a horseshoe circumflexum (Buckton) 

— Ill at most equal to cornicles. Abdomen not marked as above 8 

8. Body black throughout cerasi (Fabricius) 

— Body not black throughout 9 

9. VI spur almost twice as long as III varians Davidson 

— VI spur but slightly longer than III rhamni (Fonsc.) 



A STNOPSIS OF THE APHIDIDAE 73 



85. Myzus aquilegiae Essig 

Shinji, Can. Ent., vol. 40, p. 49, 1917. Mysm sp. (list). 

Essig, Univ. Calif. Publ. Entom., vol. 1, p. 314, 1917 (orig. desc). 

Records. — Aquilegia truncata; Berkeley, 1916 (Essig) : A. vulgare, Inverness, 
Marin County (Shinji). 

This .species was recently described by Essig from specimens found 
on columbine on tlie campus of tbe University of California, Berkeley. 
The author has had access to cotype specimens, although he has never 
collected it himself. 



86. Myzus braggii Gillette 

Figure 176 

Gillette, Can. Ent., vol. 11, p. 17, 1908 (orig. desc). 

Davidson, Jour. Econ. Ent., vol. 5, p. 409, 1912. Phorodon carduinum 
(Walker) (list). 

Becords. — Cynara scolymus; Courtland, Oakland, and San Jose (Davidson) ; 
Riverside, January and February, 1917. 

The author found this species during tlie early spring of 1917 
infesting the leaves of artichoke in Riverside. The determination of 
specimens was verified by C. P. Gillette. Davidson reported Phorodon 
carduinum (Walker) from artichoke in the San Francisco Bay region. 
His specimens were determined by J. Monell, but P. Van der Goot 
was doubtful as to its identity. Davidson himself has decided that 
the species is Myzus braggii Gillette. There is no doubt but that the 
species on artichoke in California is 31. braggii Gillette, but whether 
or not this is the same as P. carduinum (Walker) is uncertain. 



87. Myzus cerasi (Fabrieius) 

Figures 112, 121, 122, 179, 307 

Fabrieius, Syst. Nat., p. 734. Aphis (orig. dese.). 

Clarke, Can. Ent., vol. 35, p. 2-52, 1903 (list). 

GOlette, Jour. Econ. Ent., vol. 1, p. 362, 1908 (desc). 

Newman, Mon. Bull. Calif. Comm. Hort., vol. 4, p. 446, 1915 (list). 

Shinji, Can. Ent., vol. 49, p. 49, 1917 (list). 

Becords. — Pnmvs cerasi; Susanville, Lassen County (Newman) ; Berkeley, 
1914, 1915, and 1916 (Essig, Shinji) ; Riverside, 1914 (Sharp) ; Fresno, June, 
1915: Prunvs domestica; Berkeley (Clarke). 



74 MISCELLANEOUS STUDIES 

The black cherry aphis is found occasionally throughout Califor- 
nia, but seldom in large enough numbers to be injurious. It infests 
the terminal leaves of cherry, and sometimes other species of Prunus, 
causing them to curl to a certain extent. Eggs are laid in the late fall 
and early winter in the crevices of the bark and near the bases of the 
buds. These hatch the following spring about the time the buds are 
opening. The first few generations consist entirelj^ of apterous 
females. In the early summer the alate females appear, and con- 
tinue to do so in each succediug generation until fall. In fact, after 
the first of July, or thereabouts, the majority of the lice produced 
are alate until the sexes appear in the fall. The first alate females 
taken by the author were on June 7, 1915. However, on April 25, 
1916, Essig found a few alate females in Berkeley. In August, 1914, 
the apterae were also found in Berkeley. 

Van der Goot makes tliis species out of the genus Myzns, using it 
as the type of his genus Myzoides. The author is inclined to follow 
him inasmuch as this is quite different from other members of this 
genus, approaching Aphis in its robust form and separated from 
that only by the length of the cornicles and presence of antennal 
tubercles. However, it has so long been considered as a species of 
Myzus that it is best to leave it so. It is not a good policy usually to 
form a new genus for one species, especially when it has for so long 
been considered as a member of another genus. 



88. Myzus circumflexus (Buckton) 

Figure 175 

Buckton, Monog. Brit. Aphides, vol. 1, p. 130, 187.5. Siplwnophora (orig. 

desc. ) . 
Gillette, Can. Ent., vol. 40, p. 19, 1908. M. vincae, n.sp. (desc). 
Davidson, Jour. Econ. Ent, vol. 3, p. 380, 1910. M. vincae Gill. (list). 
Shinji, Can. Ent., vol. 49, p. 49, 1917 (list). 

Bccord. — Vinca major; Stanford University (Davidson, Morrison), Berkeley, 
1915 (Shinji), Los Angeles, March, 1917; Aesculiis californicus, Alopecurus 
pratensis, Asparagus, spp., Ceanothus sp., Ccrastium viscosum, Cheirantlms chicri, 
Cyrtonium falcatum, Digitalis purpurea, Fuchsia sp., Gladiolus sp., Plantago sp., 
Senecio mikanioides, Sisymbriitm sp., Solanum spp., Stachys hullata, Tropaeolum 
sp., Symphoricarpus racemosus; Berkeley, 1915, 1916 (Essig, Shinji) : Viola tri- 
color; Stanford University, March, 1915; Berkeley, 1915 (Essig, Shinji): 
Biohardia africana; Pomona, 1909 (Essig); Stanford University, March, 1915; 
Berkeley, March, 1915 (Essig) ; San Diego, May, 1916; Los Angeles, March, 1917. 

This very common aphid is found in the spring on a large variety 
of host plants throughout California. At times it may become so 



A STNOPSIS OF THE A PHI DID AE 75 

abundant as to cause some considerable damage to its liost. On March 
4, 1917, the author observed it on periwinkle in Los Angeles in such 
numbers as to stunt the flowers and to cause all the plants to appear 
black and stickj'. The apterae of this species are readilj' recognized 
by the black horseshoe-shaped marking on the doi'sum of the abdomen. 



89. Myzus cy-nosbati (Oestlund) 

OestluBd, Minn. Geol. and Nat. Hist. Surv., Bull. 4, p. 81, 1887. Nectaro- 

phora (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 10, p. 294, 1917 (note). 
Shinji, Can. Ent, vol. 49, p. 49, 1917. M. ribis (Linn.) (list). 

Eec&rds. — Sibes vulgare ; Walnut Creek (Davidson); Bibes glutinosum, B. 
memiesii; Berkeley, April, 1915 (Shinji). 

This species has been taken bvit a few times in the San Francisco 
Bay region ; once on cultivated red currant in company with Aphis 
neomexicana pacifica, once on wild flowering currant, and once on 
wild canyon gooseberry. Furthermore, only the sexapura (migrants) 
and sexuales have been taken. Davidson writes that this is true 
cynosbati of Oestlund and not the species described by Davis (Ann. 
Ent. Soc. Am., vol. 2, p. 38, 1909), as MacrosipJntm cynosbati (Oest.), 
wliich is not that species but some other. Shinji listed M. ribis 
(Linn.), but liis specimens prove to be the sexuales of this species. 

90. Myzus fragaefolii Cockerell 

Figure 177 

Cockerell, Can. Ent., vol. 33, p. 101, 1901 (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 7, p. 135, 1914 (desc. sexuales). 

Becords. — Fragaria chiloensis; Walnut Creek, Contra Costa County (David- 
son) ; Berkeley, March to September, 1915; Palo Alto, April, 1915; Ontario, 
April, 1917; Buena Park, Orange County, May, 1917 (E. K. Bishop); Santa 
Barbara, May, 1917; Eialto, San Bernardino County, May, 1917 (A. B. Snow): 
F. calif ornicus ; Pine Hills, San Diego County, June, 1916. 

On the under side of the leaves of native and cultivated straw- 
berries this small yellowish aphid is often found, both in the San 
Francisco Bay region and in southern California. Seldom does it 
become abundant, although several records of its abundance were 
received from various parts of the south during the spring of 1917. 
Several growers have thought it bad enough to spray for it. During 
the late winter (January and February) the sexuales appear and 
the eggs are laid. These hatch in a short time, and during the rest 
of the year tlie alate and apterous viviparae are found. 



76 MISCELLANEOUS STUDIES 



91. Myzus lycopersici (Clarke) 

Clarke, Can. Ent., vol. 35, p. 253, 1903. N ectaropliora (orig. desc). 
Davis, Can. Ent., vol. 46, p. 123, 1914 (desc). 

Becord. — Lycopersicum eseulentum; Berkeley (Clarke). 

Only once has this species been found in California. Davis in 
1914 described a species from tomato in Idaho, Montana, and Oregon 
which he believed to be this one. It may be, and it may not be so. 
That can never be decided for the t j'pes of Clarke 's species are all lost. 



92. Myzus rhamni (Clarke) 

Figure 178 

Clarke, Can Ent., vol. 35, p. 254, 1903. Nectarophora (orig. desc). 
Shinji, Can. Ent., vol. 49, p. 49, 1917. M. rhamni (Boyer) (list). 

Records. — Bhavmus californicus; Berkeley (Clarke), Berkeley, March, 1915 
(Shinji). 

In March, 1915, George Shinji took a species of Myzus from coffee- 
berry in Berkeley. This fits Clarke's description of Nectarophora 
rhamni, in so far as the description goes. The author considers it to 
be the same species as described by Clarke, inasmuch as it was collected 
in tlie same locality and on the same host plant. 

Wilson (Can. Ent., vol. 44, p. 156, 1912) describes a species from 
Bhamnus purshmn-a in Oregon as M. rhamni (Boyer), listing Clarke's 
species as a synonym. This is the same species as taken by Shinji 
in Berkeley, but it is doubtful if it is the species described by Boyer 
de Fonscolombe. Specimens in the author's collection from Ehamnus 
in Colorado are determined bj' Gillette and Bragg to be Aphis rhamni 
Fonsc. These are certainly different from the coast species, the former 
being an Aphis closely related to A. euonomii Fabr., the latter a 
Myzns. Prom this evidence the author cannot follow Wilson in 
placing Nectarophora rhamni Clarke as a synonym of Aphis rhamni 
Fonsc., considering both as Myzus, but he considers them as distinct, 
Clarke's species being a Myzus, Fonscolombe 's an Aphis. 



93. Myzus ribifolii Davidson 

Davidson, Jour. Econ. Ent., vol. 10, p. 294, 1917 (orig. desc). 

Becord. — Ribes glutinosum; Redwood Canyon, Contra Costa County (David- 
son). 



A SYNOPSIS OF THE APHIDIDAE 77 

Davidson recently described all forms of this species from speci- 
mens taken during March, April, and May, 1913, 1914, and 1915, on 
wild flowering currant in Redwood Canyon, Contra Costa County. 
The author is unacquainted with the species. 



94. Myzus varians Davidson 

Davidson, Jour. Econ. Ent., vol. 5, p. 409, 1912 (orig. desc). 
Becord. — Clematis ligusticifolia; San Jose (Davidson). 

Davidson found this species on the under side of the leaves of 
wild clematis, or Yerhade chivato, near San Jose, and later in Walnut 
Creek, Contra Costa County. The author is unacquainted with the 
species. 

25. Genus Nectarosiphon Schouteden 

Schouteden, Aphidologische Notizen, Leipzig, 1901. Type Macrosiplmm 
rubicola Oestlund, n.n. for Macrosiphum Oestlund, preoccupied. 

Key to California Species 
1. Body quite large, being about 3 to 4 mm. in length. Wings with dusky spot 

near tip rubicola (Oestlund) 

— ■ Body not so large, being only about 1.5 mm. long. Wings \rithout dusky spot 
near tip morrisoni Swain 



95. Nectarosiphon rubicola (Oestlund) 

Figures 107, 109, 123 

Oestlund, Minn. Geol. Nat. Hist. Surv., vol. 14, p. 27, 1886. Macrosiphum 

(orig. dese.). 
Davidson, Jour. Econ. Ent., vol. 7, p. 136, 1914. Amphorophora (list). 

Eecords. — Subus nutkanus; Contra Costa County (Davidson) ; Berkeley (Essig, 
Shinji). 

This species is sometimes found infesting the tender leaves and 
shoots of thimbleberry in the San Francisco Bay region. The most 
distinctive character which readily separates it from Amphorophora 
rubi (Kalt.) is the presence of a dusky patch near the tip of the fore- 
wing. This was originally described by Oestlund as the type of his 
genus Macrosiphum. However, this name was preoccupied by Macro- 
siphum, Passerini, so Schouteden proposed the name Nectarosiphon 
for this genus. Davidson listed this species as Amphorophora, and 
Morrison writes that he has never been able to satisfy himself why 



78 MISCELLANEOUS STUDIES 

this is not Amphorophora instead of Ncctarosiphon. There is con- 
siderable difference in the antennal tubercles of this species and 
species of Amphorophora, although otherwise they are quite similar. 
The author believes that slight as the difference is it should be recog- 
nized for it is througli the shape and size of the antennal tubercles 
that the different genera of the Macrosiphini are recognized in a 
large part. In this species the tubercles are large and distinct and 
neither gibbous nor toothed on the inner side, and with the outer side 
quite evident, while in Amphorophora they are small and distinctly 
toothed on the inner side, with the outer side a mere line, or not at 
all evident. 



96. Nectarosiphon morrisoni Swain 

Figures 124 to 127 

Swain, Trans. Am. Ent. Soc, vol. 44, p. 8, 1918. 

Records. — Cupres.ftts macrocarpa; San Francisco (Compere, Morrison), San 
Diego (Swain) : C. gnaduhipensis; San Diego (Swain). 

In Golden Gate Park, 8an Francisco, and in Exposition Park, San 
Diego, this species has been taken on cypress. The small, slender, 
long-legged apterae are found infesting the terminal leaves of the 
host. Occasionally an alate female is seen. In San Diego, the apterae 
were found in company with Cerosipha cupressi Swain. 



26. Genus Pentalonia Coquerel 

Coquerel, Ann. Ent. Soc. France, vol. 7, p. 239, 1860. Type P. nigro- 
nervosa n.sp. 

97. Pentalonia nigronervosa Coquerel 

Coquerel, Ann. Ent. Soc. France, vol. 7, p. 239, 1860 (orig. desc). 
Wilson, Jour. Econ. Ent., vol. 2, p. 346, 1909 (desc). 

Mecord. — Fdargonium sp.; Stanford University (Morrison). 

The following note concerning this species is from Morrison: 
Pentalonia nigronervosa Coquerel. See Wilson, Jour. Econ. Ent., 1909. In 
the Davidson collection (belonging to Stanford University) there is a single 
glycerine jelly mount of this species. I have been able to see enough of it to be 
certain of its identity with that described by WUson in the Journal (above). The 
record is from geranium, and Davidson once told me that he found it in alcohol 
in the laboratory [of Stanford University] at the time he began his study of the 
Aphididae. I believe the record should be published. 



A SYNOPSIS OF THE APEIDIDAE 79 

27. Geiins Phorodon Passpriiii 
Passeriui, Gli Afidi, 1860. Type P. humuli Schr. 

No attempt has been made to formulate a key to the California 
species of this genus, owing to the fact that the author has specimens 
of but one species, and that the description of the other is quite inade- 
quate. Four species have been reported from this state, two of which 
prove to be species of other genera and one of which is very doubtful. 
Phorodon carduinuin (Walker) as reported by Davidson, is Myztis 
hraggi Gillette. Phorodon galeopsidk (Kalteubach), also reported by 
Davidson, is B.hopalosiphum hippophaaes Koch. There is much 
diversity of opinion concerning the specific determination of these 
species and of Myzus clacagni Del Guercio. One might refer to Gil- 
lette's paper on Bhopalosiphum hippophoaes Koch and 3Iyzus braggii 
Gillette. Davis writes that he is not prepared to be quoted. Davidson 
lists P. galeopsidu and R. hippophoaes as synonyms. He states that 
his specimens listed as P. carduinum Walker were determined by 
Monell, but that Van der Goot is doubtful, while he himself believes 
them to be M. braggii Gillette. He has been followed in so listing 
them. This then leaves but two species reported from California. 

98. Phorodon humuli (Schrank) 

Figures 115 to 118 

Sehrank, Fauna Boica, vol. 2, p. 110, 1801-02. Aphis (orig. desc). 

Clarke, Can. Ent., vol. 35, p. 252, 1903 (list). 

Clarke, Calif. Agri. Exp. 8ta., Bull. 160, 1904 (econ.). 

Parker, U. S. Dept. Agri., Bull. Ill, 1913 (econ.). 

Vosler, Men. Bull., Cal. Comm. Hort., vol. 2, p. 668, 1913 (list). 

Eecords. — Humulris spp. ; Berkeley (Clarke); Placer County (Vosler); Berke- 
ley, July to September, 1915: Prunus domesUca; Berkeley, March to April, 1915 
(Essig, Shinji) ; (Parker). 

This is the common hop plant louse found throughout the central 
part of the state. D\iring the summer it is common on hops, but in 
the fall the sexupara migrate to plum, where the eggs are laid. These 
eggs hatch the following spring into stem mothers which feed on the 
opening buds of plum. During later generations, probably about the 
third or fourth, alate fundatrigeniae appear, which leave the plum 
and migrate to hop. Here the summer generations are produced until 
well into the fall. Parker states that the normal life cycle is as just 
stated, but that it is also possible, and it occasionally occurs, that this 



80 MISCELLANEOVS STUDIES 

aphid maj- live the entire .year upon hops, or on plum, generation after 
generation of parthenogenetic females being produced. 



99. Phorodon scrophulariae Thomas 

Thomas, Ann. Eep. 111. St. Ent., vol. 8, p. 72, 1879 (orig. desc). 
Clarke, Can. Ent., vol. 35, p. 252, 1903 (list). 

Record. — Scrophularia sp., Berkeley (Clarke). 

This is a doubtful species, reported bj' Clarke as present on 
Scrophularia in Berkeley, and by Dr. Thomas in 1879 on a species 
of plant which he thought to be Scrophularia in Illinois. Since 
Clarke's record it has never been found, although Morrison states 
that he has .spent considerable time examining the conmion Scrophu- 
laria plants in the vicinity of Stanford University, but to no avail. 
The author attempted to find it many times in the vicinity of San 
Diego during 1916, and in the vicinity of Riverside in 1917, with no 
success. 

28. Genus Rhopalosiphum Koch 
Koch, Die Pflanzenlause, p. 23, 1854. Type Aphis persicae Sulz. 

This genus is very closely related to Myzvs, and is distinguished 
only by the shape of the cornicles. This distinction is variable, how- 
ever, as in some species certain forms have the clavate cornicles of 
Rhopalosiphum while other forms have the cj'lindrical cornicles of 
Jlyzus. This is particularly true in the case of Rhopalosiphum 
persicae (Sulz.) and Myzus braggii Gillette. However, most aphidol- 
ogists separate these two genera, so the author feels that it is best 
to do so. 

Key to California Species 
Alate viviparous females 

1. Grounil color dark (olive-^een, wine, brown, and so forth) 2 

— Ground color light, usually green (this does not refer to the dark markings 

on head, thorax, or abdomen, but rather to the ground color of the 
abdomen) 4 

2. Wing veins with smoky borders and tips (fig. 164). IV with a few small 

sensoria '. violae Pergande 

— Wing veins without smoky borders or tips, and IV without sensoria. 

rhols Monell 

3. Antennae distinctly tuberculate, with sensoria on both III and IV (figs. 170, 

279) 4 

— Antennae not tuberculate, and IV without sensoria, or at most with but a 

few small ones (figs. 167, 168) 5 



A SYNOPSIS OF TEE APHIDIDAE 81 

4. VI spur slightly longer than III (figs. 279, 281). Cornicles quite large and 

heavy (figs. 282, 284) lactucae (Kalt.) 

— • VI spur about twice as long as III. Cornicles comparatively small and slender 
(fig. 165 ) blppophoaes Koch. 

5. First discoidal vein with distinct, smoky border, second discoidal bordered 

slightly so (fig. 166) nervatum Gillette 

— ■ First and second discoidal without smoky borders 6 

6. Abdomen with dusky dorsal markings. Ill with a few (10-12) sensoria 

(fig. 168) persicae Sulz. 

— Abdomen without dusky dorsal markings. Ill with many (24-30) sensoria 

(fig. 167) corylinum Davidson 

Apterous viviparous females^^ 

1. Ground color dark (olive-green, wine, brown) 2 

— • Ground color light (green, and so forth) 3 

2. Cornicles large and stout, longer than III rhois Monell 

— Cornicles smaller and more slender, shorter than III vlolae Pergande 

3. Cornicles longer than III 4 

— Cornicles shorter than III 5 

4. VI spur considerably longer than III, and subequal to cornicles. 

nervatum Gillette 

— VI spur about equal to III, and distinctly shorter than cornicles. 

hippophoaes Koch. 

5. Ill with secondary sensoria lactucae (Kalt.) 

— Ill with no secondary sensoria persicae (Sulz.) 



100. Rhopalosiphum corylinum Davidson 

Figure 167 

Davidson, Jour. Econ. Ent., vol. 7, p. 134, 1914 (orig. desc). 
Secords. — Corylus rostrata; Walnut Creek, Contra Costa County (Davidson) : 
Physocarpus capitatus; (Davidson). 

This species was originall.y described from specimens of alate 
viviparae and pupae taken on wild hazelnut near Walnut Creek. 
Davidson writes that he has found it quite common on nincbark in 
the San Francisco Bay region. The author has never taken the 
species, but has had access to cotype specimens in Essig's collection. 

101. Rhopalosiphum hippophoaes Koch 

Figures 165, 170 

Koch, Die Pflanzenlause, p. 28, 1854 (orig. desc). 

Davidson, Jour. Econ. Ent., vol. 7, p. 136, 1914. Plwrodon galeopsidis 

Kalt. (list). 
Gillette, Jour. Econ. Ent., vol. 8, p. 373, 1915 (synonomy). 

Becord. — Polygonum sp. ; San Jose (Davidson). 



12 E. corylinum Dvdn. is omitted from this key as the apterous female was 
never described and specimens are not available to the author. 



82 MISCELLANEOVS STUDIES 

Davidson reported this species as present on knotweed in the 
vicinity of San Jose, under the name P. galeopsidis Kalt. Later he 
followed Gillette in placing it as a synonym of R. hippophoaes Koch. 
The author has never collected it, hut has had access to specimens 
from Davidson in San Jose, and Davis in Oak Park, Illinois. For a 
full discussion of the synonymy of this species see Gillette's paper 
listed above. 

102. Rhopalosiphum lactucae (Kalt.) 

Figures 277 to 28-5 

Kaltenbach, Monog. d. Pflanzenlause, p. 37, 1843. Aphis (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 277, 1910 (list). 

Eccords. — Sonchiut spp.; Stanford University (Davidson); Stanford Univer- 
sity, May to July, 1915; Walnut Creek, May, 1915 (Davidson); Berkeley, July, 
1915; Lemon Grove, San Diego County, January, 1916; Eiverside, January to 
May, 1917; Los Angeles, April, 1917: Asclepias sp.; Corvallis, Oregon, November, 
1913 (Moznette). 

This is a common species infesting the heads of sow thistle 
throughout the San Francisco Bay region and southern California. 
In November, 1913, G. F. Moznette took it on milkweed in Corvallis, 
Oregon. This collection consisted entirely of alate females, that may 
have been the sexupara. Inasmuch as the identity of this species is 
doubtful there is given below a brief description drawn from speci- 
mens of nine alates and eight apterae taken on Sovchus spp. at Stan- 
ford University in May, 1915, in "Walnut Creek in May, 1915, in 
Berkeley in July, 1915, and in Lemon Grove in Januai-y, 1916, and 
on Asclepias sp. in Corvallis, Oregon, in November, 1913. This latter 
collection is by George F. Moznette of Corvallis. 

Alate viviparous female. — Prevailing color is apple green with 
the head dark green to black, the prothorax apple green, the thoracic 
lobes black. The abdomen is apple green with three pair of dusky 
marginal spots on segments one, two, and three, respectively, and 
with a larger dusky patch on the dorsum of segments four, five, and 
six, being between the cornicles. The cornicles and cauda are luteous 
with the extreme tip of the former dusky. The antennae are dusky 
throughout. The legs are luteous with the tarsi and tips of the femora 
and tibiae dusky. 

The head is about twice as broad as long, with a distinct frontal 
tubercle (fig. 278). The antennae are set on distinct tubercles and 
are between one and one-fourth to one and one-half times as long 



A SYNOPSIS OF THE APHWIDAE 83 

as tlie body. Tlio relative lengths of the segments are as follows: the 
spur is the longest, being followed by III, which is subequal but never 
longer. IV is about one-half the length of the spur and slightly longer 
than V. II is slightly longer than VI, which is about equal to I. 
Sensoria are arranged as follows (figs. 279-281) : on V and VI are 
the usual primary and accessory sensoria ; on V in addition to the 
primary sensoria. there are at times a.s many as seven small circular 
secondary sensoria, located about the middle of the segment. The 
number of these sensoria range from none to seven, two and three 
being the usual number; on IV there are from six to twelve irregular 
secondarj- sensoria (fig. 280), placed irregularly along the whole 
length of the segment ; on III there are between thirt.y and forty 
irregularly placed and irregularlj- sized sensoria (fig. 279) scattered 
along the whole length of the segment. The usual number is from 
thirty-six to thirty-nine. The prothorax is without lateral tubercles. 
The beak is of medium length, reaching to slightly beyond the second 
coxae. The cornicles (fig. 282) are fairly large and clavate on one 
side. At the widest point they are slightly less than one-fifth the 
length. The tip is .slightly wider than the base. They are about the 
same length as the fourth antennal segment, although in some cases 
they may be slightly longer, and in others slightly shorter, but in all 
eases longer than the fifth antennal segment. The cauda (fig. 283) is 
long and fairly large, not quite reaching to the tip of the cornicles, 
being about one-half as long as the cornicles and one-half as long 
again as the hind tarsi. The wings and venation are nomial, the 
forewings being about twice as long as the body. 

Measurements : Body length, 1.48 to 1.87 mm. ; width, 0.73 to 0.82 
mm. ; antennae total, 2.35 to 2.51 mm. ; III, 0.544 to 0.697 mm. ; IV, 
0.306 to 0.425 mm.; V, 0.218 to 0.357 mm.; VI, 0.085 to 0.119 mm.; 
spur, 0.68 to 0.799 mm. ; cornicles, 0.323 to 0.459 mm. ; cauda, 0.187 to 
0.255 mm. ; hind tarsi, 0.136 to 0.153 mm. ; wing length, 3.4 to 3.8 mm. ; 
wing width, 1.2 to 1.5 mm. ; wing expansion, 8.0 to 8.3 mm. The 
average measurements are as follows : body length, 1.74 mm. ; width, 
0.768 mm. ; antennae total, 2.445 mm. ; III, 0.645 mm. ; IV, 0.382 mm. ; 
V, 0.328 mm.; VI, 0.107 mm.; spur, 0.753 mm.; cornicles, 0.403 mm.; 
cauda, 0.248 mm. ; hind tarsi, 0.139 mm. ; wing length, 3.6 mm. ; width, 
1.32 mm. ; expansion, 8.1. 

Apterous viviparous fern-ale. — Prevailing color pale green with the 
head paler, being almost luteous or of a pale j-ellowish green color. 
The eyes are red. The antennae, except the apices of segments three 



84 MISCELLANEOUS STUDIES 

to six inclusive, the legs, except the tarsi and tips of the tibiae, the 
Cauda, and the cornicles, except the tip, are all luteous. Sensoria are as 
follows: on V and VI the usual primary sensoria, on VI the accessory 
sensoria, and on III (fig. 278), from nine to eleven small, circular 
irregularly placed secondary sensoria. IV is without sensoria. The 
antennae are considerably longer than the body, the spur and III 
being subequal and the longest segments. Sometimes the spur is 
slightly longer than III. V is about one-half as long as III or the 
spur, and about four-fifths as long as IV. I and VI are subequal, 
being about one-seventh as long as the spur. The cornicles (fig. 284), 
are clavate, quite large, usually being slightly more than one-fifth 
the length of the body and over three times the length of the hind 
tarsi. The cauda (fig. 285) is long, sickle-shaped, and a little more 
than one-half as long as the cornicles. 

Measurements: Body length, 1.7 to 2.18 mm.; widtli of abdomen, 
0.82 to 1.73 mm.; antennae total, 2.32 to 2.48 mm.; Ill, 0.646 to 
0.714 mm. ; IV, 0.391 to 0.425 mm. ; V, 0.323 to 0.34 mm. ; VI, 0.102 
mm. ; spur, 0.646 to 0.782 mm. ; cornicles, 0.459 to 0.493 mm. ; cauda, 
0.238 to 0.272 mm.; hind tarsi, 0.136 to 0.153 mm. The average 
measurements are as follows : body length, 1.87 mm. ; width, 0.99 mm. ; 
antennae total, 2.39 mm. ; III, 0.674 mm. ; IV, 0.408 mm. ; V, 0.334 
mm. ; VI, 0.102 mm. ; spur, 0.7099 mm. ; cornicles, 0.473 mm. ; cauda, 
0.255 mm. ; hind tarsi. 0.1445 mm. 



103. Rhopalosiphum nervatum Gillette 

Figures 166, 169, 171 

Gillette, Can. Ent., vol. 40, p. 63, 1908 (orig. desc). 

Davidson, Jour. Econ. Ent., vol. 3, p. 378, 1910. B. arbuti, n.sp. (desc). 

Davidson, Jour. Econ. Ent., vol. 7, p. 134, 1914 (list). 

Secords. — Arbutus menziesii; Stanford University, San Jose, Walnut Creek 
(Davidson); Sacramento (Essig) ; Stanford University, February to May, 1915; 
Berkeley, September, 1915: Arbutus unedo ; Redlands, February, 1917; Bosa spp. ; 
Walnut Creek (Davidson); Berkeley, February, 1915 (Essig). 

In 1910 Davidson described a species of Rhopalosiphum, which he 
named arhvti, from specimens taken on madrone in the vicinity of 
Stanford University. Since then it has been found quite commonly 
on madrone throughout the San Francisco Bay region, and once on 
a strawberry tree in Silva Park, Redlands. It was noticed by the 
author that the alate females were very scarce at all times, although 
the apterae and nymphs were often quite abundant. Later, when 



A S7N0PSIS OF THE APHIDIDAE 85 

studying specimens while working up a key to the species of Rhopalo- 
siphum, he found tliat structurally this species was identical with 
Ehopalosiphum nervatum Gillette. The latter had been taken on roses 
in the San Francisco Bay region. The identical structure and the 
scarcity of alates on madrone led to a belief that they were the same 
species. However, it was too late in the season (October, 1915) to 
trj' any transfer tests. No opportunity was found to try migration 
tests until in Februai-y, 1917, when the species was taken in Redlands. 
Two alate females were reared in the laboratory and then placed 
under a muslin bag on a rose bush, out of doors. A few daj's later 
these were examined and several young larvae observed. No further 
observations were made for two weeks, when it was found that the 
bag had been ripped off by the severe winds. Although this test was 
not a complete success the author feels confident of the identity of 
this species. 

104. Rhopalosiphum persicae^' (Sulz.) 

Figures 108, 119, 120, 168 

Sulzer, Kan. Ins., p. 10.5, 1761. Aphis (orig. desc). 

Clarke, Can. Ent., vol. 35, p. 2.52, 1903. Shopalosiphum dianthi (Schrank) 

(list). 
Gillette, Jour. Econ. Ent., vol. 1, p. 359, 1908. Myzus (desc.). 
Davidson, Jour. Econ. Ent., vol. 2, p. 303, 1909. B. dianthi (Schrank), 

B. achjirantes Monell, and Mi/eus (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. B. tulipae Thomas (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 378, 1910. B. dianthi (Schr.) (list). 
Davidson, Jour Econ. Ent., vol. 3, p. 379, 1910. Myzus (list). 
Essig, Pom. Jour. Ent., vol. 3, p. 598, 1911. Myzus (desc). 

Secords. — Throughout California by Clarke, Davidson, Essig, Ferris, Morrison, 
and the author on Aiutilon sp., Amaranthus retrofiexus, Amsiyickia respectabilis, 
Bougainvillaea sp., Brassica spp., Capsella bursa-pastoris. Capsicum annuum, 
Catalpa sp., Chenopodium murale, Citrus spp., Cynoglossum grande, Cyticus pro- 
liferus, Geranium carolinianum, Hedera helix, Lycopersioum esculentum, Malva 
parviflorus, Oxalis oregona, Prunus spp., Banunculus californicus, Eaphanus 
sativU'S, Bumex spp., Sambu/^us glauca, Sanicula inenziesii, Senecio vulgare, 
Solanum tuberosum, Sonchus spp., Tropaeolum sp., Tulipa sp., Vinca major. 

This green peach aphis is one of the most common aphids found 
in the state. It is most abundant in the spring, at which time it will 
be found on almost any plant. According to Gillette various species 



13 George Shinji (Can. Ent., vol. 49, p. 49, 1917) recently described an aphid 
from specimens taken on Godetia amacna in Berkeley, which he named Myzus 
godetiae n.sp. The author has not seen specimens of this species, but from the 
description and figures, it is in all probability Bhopalosiphum. persicae (Sulz.). 



86 MISCELLANEOUS STUDIES 

of Prmuis are the winter hosts iu Colorado, while during the sununer 
it migrates to other plants. In California, however, winter eggs are 
not laid, the viviparous females living the year round. So far as tlic 
author has observed in over three years, only the form with elavate 
cornicles is found in California. 



105. Rhopalosiphum rhois Monell 

Figure 173 

Monell, V. S. Geol. Geog. Surv., Bull. 5, p. 27, 1879 (orig. desc). 
Davis, Can. Ent., vol. 46, p. 165, 1914. R. howardi (Wils.) (desc). 
Essig, Univ. Calif. Publ. Ent., vol. 1, p. 330, 1917. K. howardi (Wils.) 

(list). 
Ibid., p. 334, 1917 (list). 

Records. — Rhus divcrsiloba; Berkeley, April, 1915; Avena satira, Berkeley, 
(Essig). 

This species has been taken in Berkeley on poison oak and grasses. 
Essig reported it recently as R. hmmirdi (Wils.), but according to 
Gillette" this is a synonym of R. rhois Monell, RMis being the winter 
host, and various species of Gramlnacrac the summer hosts. 

This species does not seem to be a typical Rhopalosiphum, being 
quite close to Siphocoryne nympharae Linn., but yet not fitting the 
generic description of Siphocoryne exactl.v. Consequently it is best 
to list it as has been done heretofore as Rhopalosiphum. 



lOf). Rhopalosiphum violae Pergande 

Figures 164, 174 

Pergande, Can. Ent, vol. 32, p. 29, 1900 (orig. desc). 
Essig, Pom. Jour. Ent., vol. 1, p. 4, 1909 (desc). 
Davidson, Jour. Econ. Ent., vol. 2, p. 303, 1909 (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 277, 1910 (list). 

Records. — Viola spp.; Claremont, Santa Paula (Essig); Stanford University 
(Davidson); Palo Alto, May, 1915; Santa Ana, February, 1917; Eiverside, April, 
1917. 

This beautiful little aphid is found more or less abundantly in the 
spring on the under side of the leaves of violets throughout the state. 
Tlie dark red color and broad black wing veins serve to distinguish it 
readily from other aphids. 



14 Gillette, Jour. Econ. Ent., vol. 8, p. 100, 1915. 



A SYNOPSIS OF THE APHIDIDAE 87 

Tribe Aphidini Wilson 

Wilson, Ann. Ent. Soc. Am., vol., 3, p. 331, 1910. 
Following is a brief characterization of this tribe, from Wilson : 

The characters which separate this tribe from tlie previous one [Macrosiphinij 
are taken as follows: Antennae shorter than the body, or when as long as the 
body the cornicles and cauda are very short; antennal tubercles, when present, 
are indistinct, or else the cornicles and cauda are small; when the cornicles are 
very long or large the development is limited and the other characters are used 
to place the genera. 

The California genera included bj- Wilson in this tribe are Ai}his, 
Cerosipha, Coloradoa, Hyalopierus, Liosomaphis, and Siphocoryne 
[Hyadaphis]. In addition to these the author includes Toxoptera 
because of the small and indistinct antennal tubercles and the short 
cornicles, and Myzaphi^ because of the absence of antennal tubercles. 
The kej' to the California genera has been formulated by the author, 
following Wilson, Mordwilko, and Van der Goot. 

1. Antennae five-segmented Cerosipha del Guercio 

— Antennae six-segmented - 2 

2. Cornicles much shorter than cauda Hyalopterus Koch 

— • Cornicles about as long as or longer than cauda 3 

3. Cornicles cylindrical, tapering, or conical, not distinctly clavate (fig. 182), 

except in Coloradoa and Myzaphis, in which they may be slightly clavate 

at the apex (fig. 315) 5 

— ■ Cornicles distinctly clavate (figs. 183, 184) 4 

4. Cornicles long and strongly clavate on one side (fig. 184). Antennae shorter 

than body, with VI spur not longer than III liiosomapliis Walker 

— Cornicles slender and but slightly clavate (fig. 183). Antennae never much 

shorter than body, with VI spur longer than III (fig. 2.58) or with a supra- 
caudal tubercle (figs. 2.5.5, 256) Siphorcoryne Passerini 

5. Third discoidal vein but one-branched (fig. 276). Body without lateral 

tubercles. Cauda long and prominent, being about as long as cornicles. 

Toxoptera Koch 

— Third discoidal vein twice-branched. Body with or without lateral tubercles. 

Cauda usually distinctly shorter than cornicles 6 

6. Front of head with a very distinct tubercle (figs. 308, 313). Body long 

without lateral tubercles. Cornicles long and often slightly swollen near 
apex Myzaphis Walker and Coloradoa Wilson 

7. Front of head without prominent tubercle (fig. 233). Body more rounded 

with lateral tubercles on prothorax and seventh abdominal segment, and 
oftentimes on some of the anterior abdominal segments Aphis Linn. 



88 MISCELLANEOUS STUDIES 



29. Geinis Aphis Linn. 
Linnaeus, Syst. Nat., 1748. Type Aphis rumicis Linn. 
Key to Califoenia Species 
Alate viviparous females 

1. Abdomen with floeculent masses of wax. Antennae considerably sliorter than 

body, and VI spur shorter than III alamedensis Clarke 

— • Abdomen without such floeculent masses of wax (except perhaps Aphis cooki 
Essig) 2 

2. Antennae one and one-half times as long as the body, or more. 

houghtonensis Throop 

— ■ Antennae not so much longer than body; when longer, which is seldom, but 

slightly so 3 

3. Abdomen pale yellowish green. Found only on Morus sp mori Clarke 

— Abdomen darker being black, dark green, yellow. Not found on Morus sp. 4 

4. Abdomen dark-green with an orange band between the cornicles. 

angelicae Koch 

— Abdomen without such an orange band between the cornicles (sometimes there 

is a slight orange or reddish coloring between the cornicles of the apterae 
of Aphis avenae Fabr., but it is not constant) 5 

5. Abdomen sage-green with faint lateral spots. Ill with apical one-half con- 

spicuously darkened and with six large sensoria. VI spur less than one-half 
as long as III. On Atriplex spp tetrapteralis Cockerell 

— Not with above combination of characters 6 

6. IV with secondary sensoria (fig. 244) 7 

— IV without secondary sensoria (fig. 204) 27 

7. Cornicles and hind tarsi subequal 8 

— Cornicles considerably longer than hind tarsi 17 

8. VI spur shorter than III 9 

— VI spur equal to or longer than III 13 

9. Cornicles short and tapering 10 

— Cornicles short and incrassate pseudobrassicae Davis 

10. V with secondary sensoria. Body slightly pulverulent cooki Essig 

— • V without secondary sensoria. Body not pulverulent 11 

11. Less than 12 secondary sensoria on III, arranged in a more or less even line 12 

— About 20 to 25 secondary sensoria on III, arranged irregularly along segment 

(fig. 244) senecio Swain 

12. Ill with 9 to 12 sensoria. V and VI base subequal, each being shorter than 

IV lithospermi Wilson 

— Ill with' 5 to 9 sensoria. IV and V subequal, each being longer than VI 

base vibumicolens n.sp. 

13. Cornicles shorter than hind tarsi. A large black species in life being marked 

with white bars and cross bands on the abdomen albipes Oestlund 

— • Cornicles and hind tarsi subequal. Body color greenish 14 

14. Koot-infesting species. Antennae short, scarcely reaching the middle of the 

abdomen middletonil Thomas 

— Aerial species. Antennae reaching to base of the cornicles, or as long as 

body 15 

15. Cornicles incrassate. A mediimi-sized species pseudobrassicae Davis 

— Cornicles cylindrical and tapering slightly. A smaller-sized species 16 



A SYNOPSIS OF THE AFHIDIDAE 89 

It). Cauda shorter than himl tarsi. Ill witli 11 to 15 sensoria scattered irregu- 
larly along segment (fig. 294) marutae Oestlund 

— Cauda longer than hind tarsi. Ill with 5 to 9 more or less evenly' arranged 

sensoria viburnicolens n.sp. 

17. Cornicles equal to or longer than III 18 

— Cornicles not as long as III 19 

18. Cauda, cornicles, and III subequal. Second branch of third discoidal vein 

very near to apex of wing spiraecola Patch 

— Cauda considerably shorter than cornicles or III, the last two being subequal. 

Second branch of third discoidal about midway between base of first 
branch and apex of wing oenotherae Oestlund 

19. Fore wing with the second branch of the third discoidal arising very near 

to the apex of the wing. (In a few eases the second branch is not found, 
but never in both wings) (fig. 191) avenae Fabr. 

— Venation of fore wing normal (fig. 187) 20 

20. Antennae longer than body persicae-niger Smith 

— Antennae not longer tlian body 20 

21. A pair of small tubercles present on the middle of the seventh and eighth 

abdominal segments malifoliae Fitch 

— Such tubercles not present 22 

22. V with secondary sensoria. VI spur longer than III 23 

— V without secondary sensoria. VI spur at most equal to III 25 

23. Beak scarcely reaching second coxae maidis Fitch 

— Beak reaching beyond second coxae, even to or beyond the third 24 

24. Cornicles longer than cauda (figs. 194, 19.5) and more than twice as long as 

hind tarsi sambucifoliae Fitch 

— ■ Cornicles and cauda subequal ; tlie former not more than twice as long as 
hind tarsi neomexicana Cockerell var. pacifica Davidson 

25. Cauda and hind tarsi subequal. Ill with a few large sensoria (fig. 232). 

Abdomen green with dark dorsal markings ramona Swain 

— Cauda longer than hind tarsi. Ill with several sensoria. Abdomen black 

or dark brown 26 

26. Cornicles more than twice as long as hind tarsi, often almost three times as 

long. VI spur and cornicles subequal, hind tarsi and VI base subequal. 

hederae Kalt. 

— Cornicles never more than twice as long as hind tarsi, usually considerably 

less. Hind tarsi usually slightly longer than VI base, and VI spur longer 
than cornicles euonoml Fabr. 

27. Cornicles distinctly knobbed, the tip being widened to twice the width of 

the rest of the cornicles frigidae Oestlund 

— Cornicles normal 28 

28. Fore wing with the second branch of the third discoidal arising very near the 

apex of the wing (fig. 188) salicicola Thomas 

— Fore wing with venation normal (fig. 187) 29 

29. Cornicles distinctly longer than cauda 31 

— Cornicles at most equal to cauda 30 

30. Cornicles short and swollen throughout apical one-half (fig. 203). Antennae 

as long as or longer than the body brassicae Linn. 

— Cornicles short and slender, and slightly clavate on one side. Antennae 

scarcely two-thirds as long as the body atripllcis Linn. 

31. Abdomen without lateral tubercles on anterior segments. Cauda short and 

broad, with rounded tip, and almost as long as the cornicles cardui Linn. 

— Abdomen with lateral tubercles on at least one of the anterior segments .... 32 



90 MISCELLANEOUS STUDIES 

32. VI spur shorter than III 33 

— VI spur not shorter than III 34 

33. Cornicles about three times as long as cauda medicaginis Koch 

— Cornicles not three times as long as cauda 34 

34. Cauda more than one-half as long as cornicles 35 

— Cauda not more than one-half as long as cornicles 38 

35. Ill with four or five fairly large sensoria oregonensls Wilson 

— Ill with many irregular sensoria 36 

36. Ill with 20 or more sensoria, IV with none 37 

— Ill with less than 20 sensoria, usually 14 or 15. IV usually with one or two, 

or more sensoria euonomi Fabr. 

37. IV about one-third longer than V. Cornicles about four times as long as 

broad at base. On Heraclium spp heraclil Cowen 

— IV but about one-sixth longer than V. Cornicles about three times as long 

as broad at base. On Tucca sp Yuccae Cowen 

38. A few (about 10) equal-sized sensoria on III (fig. 222). A large yellow 

species with distinct dark markings nerii Fonsc. 

— About 20 irregular sensoria on III (fig. 211). Not yellow 39 

39. Cornicles slightly more than twice as long as hind tarsi 40 

— Cornicles not twice as long as hind tarsi carl Essig 

40. Hind tarsi slightly longer than cauda ceanothl Clarke 

— Hind tarsi shorter than cauda comifoUae Fitch 

41. VI spur one and one-half or more times as long as III setariae Thomas 

— VI spur never so much longer than III 42 

42. Ill with a few large circular sensoria (5-10) (figs. 226, 290) 43 

— Ill with several (15 or more) irregular sensoria 45 

43. Beak reaching to or beyond third coxae. IV never with sensoria. 

gossypli Glover 

— Beak not reaching third coxae 44 

44. VI spur longer than III (fig. 226). Small size pomi de Geer 

— VI spur subequal to or shorter than III (figs. 289, 290). Medium to large 

size cerasifoliae Fitch 

45. Cornicles twice as long as cauda. Femora of all three pairs of legs similarly 

colored carl Essig 

— Cornicles longer than cauda, but not twice as loag. Femora of first pair of 

legs pale, of second and third pair black euonomi Fabr. 

Apterous viviparous femalesi^ 

1. Cornicles shorter than hind tarsi 2 

— • Cornicles equal to or longer than hind tarsi 4 

2. VI spur longer than III. White bars and bands on abdomen in life. 

alblpes Oestlund 

— VI spur not longer than III. Abdomen not as above 3 

3. Cornicles and cauda subequal. Beak not reaching to second coxae. Pul- 

verulent brassicae Linn. 

— Cornicles shorter than cauda. Beak reaching to or beyond second coxae. Not 

pulverulent atripUcls Linn. 

15 In this key only those species are included of which there are specimens in 
the author's collection or of which there are adequate descriptions available. 
The following species are therefore omitted: Aphis alamedensis Clarke, A. hough- 
tonensis Throop, A. inori Clarke, A. neomexicana Cockerell, A. oenotherae Oest- 
lund, and A. tetrapteralis Cockerell. 



A SYNOPSIS OF THE APSIDIDAE 91 

4. Cornicles and hind tarsi subequal : 5 

— Cornicles longer than hind tarsi 10 

5. Secondary sensoria on III and IV. Root species _ mlddletonii Thomas 

— No secondary sensoria. Aerial species 6 

6. Ill longer than VI spur 7 

— Ill shorter than or at most equal to VI spur 8 

7. IV and cornicles subequal llthospermi Wilson 

— IV shorter than cornicles. Pulverulent cooki Kssig 

8. IV and cornicles subequal. Antennae considerably more than one-half the 

length of the body 9 

— IV shorter than cornicles. Antennae at most one-half the length of the body. 

senecio Swain 

9. Cornicles twice as long as cauda and slightly swollen before the tip. 

avenae Fabr. 

— Cornicles not twice as long as cauda, cylindrical, and tapering toward tip. 

marutae Oestlund 

10. Cornicles less than twice as long as hind tarsi 11 

— Cornicles twice as long as or longer than hind tarsi 21 

11. Secondary sensoria on III and IV. Root-infesting species. 

mlddletonii Thomas 

— No secondary sensoria. Aerial species 12 

12. VI spur longer than III 1 13 

— VI spur at most equal to III 16 

13. Ground color, black or dark brown 14 

— Ground color, a shade of green 15 

14. VI spur one and one-half to two times as long as III. Apex only of femora 

dusky setarlae Thomas 

— VI spur but slightly longer than III. Apical one-half of femora dusky. 

medecaginis Koch 

15. Pale green. Cornicles and cauda subequal. Dark, mottled green. Cornicles 

twice as long as cauda or longer avenae Fabr. 

16. VI spur considerably shorter than III 17 

— VI spur almost as long as III 18 

17. Cornicles swollen toward tip pseudobrassicae Davis 

— Cornicles cylindrical and tapering toward tip ramona Swain 

18. Cornicles but slightly longer than hind tarsi 19 

— Cornicles about one and one-half times as long as hind tarsi 20 

19. Dark green. Cornicles at least three times as long as broad at base. 

maidis Fitch 

— Pale green. Cornicles at most twice as long as broad at base. 

senecio Swain 

20. Dark green to reddish yellow. On Yu^ca spp yuccae Cowen 

— Black or very dark brown with black dorsal bands and spots. On various 

plants euonomi Fabr. 

21. Cornicles distinctly knobbed at tip frlgidae Oestlund 

— Cornicles normal 22 

22. VI spur longer than II 23 

— VI spur at most equal to III 25 

23. Pale green with dusky dorsal abdominal markings calendulicola Monell 

— Not colored as above, either not green, or if green with dusky dorsal abdom- 

inal markings 24 



92 MISCELLANEOUS STUDIES 

24. Bright yellow with black markings. Cornicles at least three times as long as 

hind tarsi nerii Fonsc. 

— Dark green with black markings. Cornicles but about twice as long as hind 

tarsi cardui Linn. 

25. Cornicles longer than III 26 

— Cornicles at most equal to III 29 

26. Ill considerably longer than VI spur 27 

— Ill subequal to or but slightly longer than VI spur 28 

27. Black. Cornicles about three times as long as hind tarsi. Ill one and one- 

half times as long as VI spur sambucifoliae Fitch 

— Green, pale to apple. Cornicles about four times as long as hind tarsi. Ill 

almost twice as long as VI spur saUcicola Thomas 

28. Cornicles subequal to or but slightly longer than III, and about twice as 

long as Cauda prunorum Fabr. 

— Cornicles one and one-half to two times as long as III, and about four times 

as long as cauda oregonensis Wilson 

29. Cornicles considerably shorter than III 30 

— Cornicles subequal to or but slightly shorter than III 37 

30. Ill and IV spur subequal persicae-niger Smith 

— Ill longer than VI 31 

31. Cornicles at least twice as long as cauda 36 

— • Cornicles not twice as long as cauda 32 

32. Pale green, pulverulent cerasifoliae Fitch 

— Dark green, brown, or black, not pulverulent 33 

33. Cornicles about three times as long as hind tarsi 34 

— Cornicles not three times as long as hind tarsi 35 

34. Ill with a few small secondary sensoria hederae Kalt. 

— No secondary sensoria cornifoliae Fitch 

35. Cornicles considerably more than twice as long as hind tarsi. Lateral abdom- 

inal tubercles only on first and seventh segments heraclii Cowen 

— Cornicles at most but slightly more than twice as long as hind tarsi. Lateral 

tubercles usually on more than first and seventh segments ....euonomi Fabr. 

36. Antennae about as long as body. Cornicles more than twice as long as 

Cauda carl Essig 

— Antennae but about one-half as long as body. Cornicles but about twice as 

long as Cauda gossypii Glover 

37. Ill considerably longer than VI spur 38 

— Ill and VI spur subequal 40 

38. A pair of dorsal abdominal tubercles on sixth and seventh segments. 

malifoliae Fitch 
— ■ No dorsal abdominal tubercles on sixth and seventh segments 39 

39. Cornicles green, cylindrical, tapering slightly toward tip, and fairly straight. 

Cauda about one and one-half times as long as hind tarsi. Abdomen with- 
out dusky dorsal markings ramona Swain 

— Cornicles black, cylindrical, curved outward. Cauda and hind tarsi subequal. 

Abdomen with dusky dorsal markings seanothi Clarke 

40. VI spur slightly longer than III. Cornicles and cauda subequal. 

vibumicolens n.sp. 

— VI spur slightly shorter than III. Cornicles one and one-half times as long 

as cauda pomi De Geer 



A SYNOPSIS OF TEE APHIDIDAE 93 

107. Aphis alamedensis Clarke 
Clarke, Cau. Eut., vol. 35, p. 2.51, 1903 (orig. desc). 
Kccord. — Pnutus domestica ; Berkeley (Clarke). 

Tills is an unknown species described from specimens taken by 
Clarke on greengage plum in Berkeley. Davidson suggests that it 
might be Aphis cardui Linn, {pruni Koch) from its brief description. 



108. Aphis albipes Oestlund 

Figures 198 to 200 

Oestlund, Geol. Nat. Hist. Surv. Minn., Bull. 4, p. 52, 1887 (orig. desc). 
WUliams, Univ. Neb. Studies, vol. 10, p. 119, 1910 (desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910 (list). 

Eecords. — Symphoricarpus raceviosus; Stanford University (Davidson) ; Con- 
gress Springs, Santa Clara County, July, 1915 (McCracken) ; Berkeley, July, 1915 
(Shinji). 

This species is found at times curling the leaves of snowberrj- in 
the San Francisco Bay region. Dr. McCracken noted in connection 
with the infestation at Congress Springs, "they are quite prettily 
patterned with white bars and cross-bars." This is usually enough 
to distinguish them. 



109. Aphis angelicae Koch. 

Koch, Die Pflanzenliiuse, p. 521, 1854 (orig. desc). 
Wilson, Jour. Econ. Ent., vol. 2, p. 348, 1909 (desc). 

Record. — Angelica sp., Hcdera sp. ; California (Wilson). 

Wilson reported this species from California, but gave no locality 
or date. It is unknown to the author. 



no. Aphis atriplicis Linn. 

Linnaeus, Fauna Sweden, p. 1000, 1761 (orig. desc). 
Hayhurst, Ann. Ent. Soc Am., vol. 2, pp. 88-100, 1909 (desc). 
Davidson, Jour. Econ. Ent., vol. 5, p. 407, 1912 (desc sexuales apterous 
viviparae). 
Davidson, Jour. Econ. Ent., vol. 7, p. 133, 1914 (desc. fundatrix). 

Sccords. — Chenopndium album, C. murale; San Jose, Walnut Creek (David- 
son). 



94 MISCELLANEOUS STUDIES 

This has been reported twice from pigweed or goosefoot in the 
San Francisco Bay region, where Davidson states that it is very 
common. The sexes occur in October. Davidson believes that there 
is an alternate host, but as to what it might be, he is uncertain. The 
author has never collected specimens, but has had access to material 
taken by R. W. Doane on Chenopodium in Utah in August, 1916. 



m. Aphis avenae Fabr. 

Figures 191, 201, 202 

Fabricius, Ent. Syst., p. 736, 1775 (orig. desc). 
Clarke, Can. Ent., vol. 35, p. 254, 1903 . Nectarophora (list). 
Davidson, Jour. Eeon. Ent., vol. 3, p. 377, 1910. Siphocori/ne (list). 
Essig, Pom. Jour. Ent., vol. 3, p. 465, 1911. A. padi Linn. (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 790, 1912. A. inaidis Fitch (desc). 
Smith, Men. Bull. Cal. Comm. Hort., vol. 3, p. 116, 1914 (list). 
Davidson, Men. Bull. Cal. Comm. Hort., vol. 6, p. 65, 1917 (note). 

Secords. — Graminaceae (various spp.) ; California, December to May (David- 
son, Essig, Morrison, author) : Phalaris arundinaccn ; Stanford University, May 
to July, 1915: Dracaena draco; Stanford University, June, 1915: Musa sapientum ; 
San Diego, March, 1916: Typha latifolia; (Davidson). 

This is an abundant species througli the state, occurring during 
the late winter and spring on grasses and grains, migrating to other 
hosts as these become ripened and dried. 

The life history of this species, according to Davis (U. S. Dept. 
Agr., Bull. Ill, April, 1914), is somewhat as follows: 

The spring colonics on grains and grasses originate from viviparous females 
which passed the winter on the grains and grasses, or from spring migrants from 
the apples or related fruits; i.e., the progeny of the aphids hatching from eggs 
laid the previous fall on such trees. As the weather becomes cooler they seek the 
lower parts or the roots of wheat and other plants of the grass family, and 
here pass the winter as viviparous females ; or the winged fall migrants from the 
grain may seek such trees as the apple, where the true sexes are produced. 

Undoubtedly the most common method of wintering over in Cali- 
fornia is on the roots and lower parts of the grains and grasses. This 
species has never been collected on apples or other related trees in 
this state, nor have the eggs ever been observed. During the early 
spring it is found abundantlj' on the grains and small grasses, in 
January and February in the southern part of the state, and during 
April and May in the central part. As the grains ripen and the 
stalks and leaves become hardened, it seems that the aphids migrate 
to other varieties of grass which remain soft and green later, as 
canary grass and reed grass and corn, or even to such hosts as the 



A SYNOPSIS OF THE APHIDIDAE 95 

dragon tree, cat-tail riisli, and the banana. But the winter is spent 
as viviparous females on the grains and grasses. 

This species has been confused many times with other species 
infesting grains, such as Macrosiphum grutiarium (Kirby) and Tox- 
optera graminum (Rond.). As the latter does not occur in this state 
it cannot be confused here with Aphis avenae Fahr. Clarke listed this 
as Ncctarophara avoiae Fabr., so it appears that he might have had 
Mdcrosiphum. granarium (Kirby) in mind, as it is highly improbable 
tliat he could have confused J^p/u's avenae Fabr. with a species of 
Macrosiphum [Nectnrophora). The cornicles of aveiKie Fabr., the 
absence of antennal tubercles, and the irregular venation make it 
quite easily distinguishable. The cornicles are quite short, as com- 
pared with a species of Macrosiphum, and distinct antennal tubercles 
are entirely lacking. The third discoidal vein of the forewing is 
typically twice-branched, but the second is close to the apex of the 
wing, and sometimes is entirely lacking. The only other species of 
Aphis in this state with this character is Aphis salicicola Thomas, 
found on willows. These two are readilj* distinguished from each 
other by the comparative lengths of the cornicles, which are consider- 
ably longer in salicicola Thomas than in avenae Fabr. 

112. Aphis brassicae Linnaeus 

Figures 203, 204 

Linnaeus, Syst. Nat., vol. 2, p. 734, 1735 (orig. dese.). 
Clarke, Can. Ent., vol. 35, p. 250, 1903 (list). 
Davidson, Jour. Ecou. Eut., vol. 2, p. 302, 1909 (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 876, 1910 (list). 
Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911 (list). 
Essig, Pom. Jour. Ent., vol. 3, p. 523, 1911 (desc). 

Secord. — Cruciferae (various spp.); throughout California. 

During tlie late winter and spring cruciferous plants are often 
heavily infested with this species. Of the cultivated plants cabbages 
and radishes seem to be most heavily infested ; while the wild mustard 
and radish often have the entire flower clusters covered with these 
aphids. Oftentimes in the colonies of this species are also found 
Aphis pseud-ohrassicae Davis, Rhopcdosiphum lactncae (Kalt.), and 
R. pcrsicae (Sulz.). In southern California the colonies are always 
attacked by the braconid fl.v, Diaretus rapae Curtiss, and a large per- 
centage of the individuals destroyed. As summer comes on these para- 
sites and such predatore as syrphids and ladybirds usually get the 
best of the aphids, which disappear to a large extent until fall. 



96 MISCELLANEOUS STUDIES 



113. Aphis calendulicola ilonell 

Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 23, 1879 (orig. desc). 
Clarke, Can. Ent, vol. 35, p. 250, 1903 (list). 

Record. — Calendula officinale; Berkeley (Clarke). 

Tlii.s species has uot beeu recognized since Clarke's report of it on 
marigold. It is possible that he had Aphis senecio Swain, which is 
very common on marigolds throughout the state. 

1]4. Aphis cardui Linn. 

Figures 208, 209 

Linnaeus, Syst. Nat., vol. 2, p. 735, 1735 (orig. desc). 

Games, Men. Bull. Cal. Comin. Hort., vol. 1, p. 399, 1912. Aphis pruni 

(list). 
Davidson, Jour. Econ. Ent., vol. 5, p. 407, 1912 (list). 
Patch, Maine Agr. Exp. Sta., Bull. 233, p. 263, 1914 (desc). 

Eecords. — Cirsiv,m sp.; San Jose (Davidson); Berkeley, June, 1915: Prunus 
domestica ; Orangevale, Sacramento County (Carnes) ; Walnut Creek (David.son) ; 
Berkeley, March, 1916 (Essig). 

According to Patch this tiiistle aphid is the same as the one infest- 
ing plums and formerlj^ known as A. pruni Koch. Both are abundant 
in the San Francisco Bay region, pruni being found in the fall and 
spring on plum, cardui during tlie summer on thistle. The author 
has attempted no transfer tests, so accepts Patch's statement as 
authority for the synonym}-. It is certain that structurally these are 
strictly identical. 

n."). Aphis cari Essig 

Essig, Univ. Calif. Publ. Eiitom., vol. 1, pp. 317-321, 1917 (orig. desc). 

Record. — Canmi kellogr/ii ; Rutlierford, Napa County (Essig); Angelica 
tomentosa ; Berkeley (Essig). 

Essig recently described this from specimens taken on wild anise 
in Rutherford. The author has seen cotype specimens, but has never 
collected the species. 

116. Aphis ceanothi Clarke 

Figures 210, 211 

Clarke, Can. Ent., vol. 35, p. 250, 1903 (orig. desc). 
Davidson, Jour. Econ. Ent,, vol. 2, p. 302, 1909 (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). 
Essig, Pom. Jour. Ent., vol. 3, p. 525, 1911. Aphis ceanothi-hirsuti n. sp. 
(desc). 



A SYNOPSIS OF THE APHIDIDAE 97 

Bccords. — Ceaiwthus intcgrrrimus; Colfax, Placer County (Clarke) ; Witch 
Creek, San Diego County, June. lOKi: C. cuncatus; Stanford University (David- 
son), November, 1910 (Morrison), October, 1915 (R. A. Vickerey) : C. thysiflorus ; 
Bear Creek Gulch, Santa Clara County, April, 1911 (Morrison) : C. hirsuti; Santa 
Paula (Essig). 

This is a widely distributed species, liaving been found on Ceano- 
thus as far north as Plaeer County, and as far south as San Diego 
County. It is seldom abundant, however. The species that Essig 
described as A. ceanoihi-hi):siiti n.sp. is undoubtedly the same as 
Clarke described. 



117. Aphis cerasifoliae Fitch 

Figtures 288 to 292 

Fitch, Bept. Ins. N. Y., vol. 1, p. 131, 1855 (orig. desc). 
Patch, Maine Agr. Exp. Sta., Bull. 233, p. 260, 1914 (desc). 

Becord. — Prunus emorginata; Wynola, San Diego County, June, 1916. 

This aphid was found abundantlj' curling the terminal leaves of 
wild cherry near Wynola (3700 feet altitude), San Diego County, in 
June, 1916. Alate and aptei-ous viviparous females as well as nymphs 
were abundant in the curled leaves. The apterae and nymphs were 
.slightlj' pulverulent. This species corresponds very closely to Aphis 
cerasifoliae Fitch as described by Patch {op. cit.), although there are 
some minor differences. Following is a copy of Patch's description of 
the Maine specimens of this species : 

This well defined species is common on both the native choke cherry, Prumis 
virginiana, and the western P. demissa Walp. introduced in a nursery row on our 
campus. 

Aptcrotis female. — Head, pale green or water wliitisli, beak short, extending 
to second coxae, eyes, antennae with I, II and III concolorous with head, distal 
half darker to black, III with no sensoria, proportions as shown in figure; pro- 
thorax pale green, lateral tubercles present; thorax green with dark green mid- 
dorsal line, femora and tibiae pale and tarsi black; abdomen pulverulent, pale 
green with dark green median line and dark green transverse lines between seg- 
ments, lateral tubercles present, cornicles pale with dusky tips, slender, slightly 
tapering, and approximately twice the tarsus in length, cauda white with dark tip ; 
conical, being broad at base and abruptly tapering. 

Nymphs and pupae are also pulverulent and have dark green niiddorsal and 
transverse intersegmental line, though these are not always well defined in the 
pupa which has two lateral dark green lines on thorax. 

Alatc female. Head black, beak short, not reaching to second coxae, eyes 
black, antennae dark. III with from about 12 to 18 large sensoria about the size 
of the terminal one on V, IV with from none to several sensoria like those on III, 
proportions of joints as shown in the figure; prothorax green with black trans- 
verse band, lateral tubercles present; thorax black, wings iridescent with slender 
brown veins and largo dusky stigma with pointed tip ; commonly though not 



98 MISCELLANEOUS STUDIES 

always with second branch very short, abdomen glabrous, rather bright though not 
vivid green, median line dark green, sutural lines dark green ending in marginal 
green dots, cornicles dark, cauda greeu. 

Aphis cerasifolUie is gregarious on the ventral surface of the terminal leaves 
badly curling and deforming them. A copious amount of honeydew is present, 
and ants are usually found attending a colony of this species. 

The specimens from W,yiiola agree very well with this description, 
although as stated above, there are a few minor points of difference. 
However, as Dr. Patch writes: "It seems too close to cerasifoliae to 
give it a distinct name," and "if the appearance in life answers my 
description of cerasifoliae I should be inclined to call it that. It hap- 
pens to be a species as characteristic alive as dead." Following are 
the notes the author took of its appearance alive, before he suspected 
its identity: "Alates, apterae and nymphs abundant on terminal 
leaves curling them badlJ^ Large amount of honeydew and many 
ants in attendance. Apterae and nymphs pulverulent." These notes 
agree exactly with Patch 's notes, cited above. 

Following is a brief description of specimens taken at Wj-nola on 
July 8 : 

Apterous viviparous female. — Prevailing color pale apple green, 
pulverulent. Head luteous. Thorax and abdomen pale green with 
middorsal longitudinal stripe darker green. Antennae with the three 
basal joints luteous, tlie three apical joints .shading into black. Pri- 
mary sensoria on V and VI, accessory sensoria on VI, no secondary' 
sensoria. Ill and spur are subequal, or III slightly the longer. IV 
and V subequal and a little more than one-half as long as III. In 
some cases IV is slightly longer than V. VI is about one-fourth as 
long as its spur, longer than I, which in turn is longer tlian II. Tjie 
antennae are longer than the body. Cornicles long, slightly tapering, 
pale with tip dusky, about eciual in length to the fifth antennal seg- 
ment and about twice the length of the hind tarsus. Cauda long, 
conical, and about two-thirds the length of the cornicles, pale with tip 
dusky. Lateral tubercles are present on the first and seventh abdom- 
inal segments and on one other of the abdominal segments, in some 
cases on the second, in otherslon the third, and in others on the fourth. 

Measurements (of specimens mounted in Canadian balsam) : Body 
length, 1.5 to 1.53 mm.; body width (abdomen), 0.247 mm.; antennae 
total, 1.445 to 1.734 mm. (av. 1.6082 mm.) ; I, 0.085 to 0.117 mm. 
(av. 0.0987 mm.) ; II, 0.068 mm.; Ill, 0.408 to 0.467 mm. (av. 0.4335 
mm.) ; IV, 0.238 to 0.306 mm. (av. 0.272 mm.) ; V, 0.221 to 0.233 mm. 
(av. 0.224 mm.) ; VI, 0.1105 to 0.119 mm. (av. 0.1169 mm.) ; spur, 



A SYNOPSIS OF THE APEIDIDAE 99 

0.408 to 0.45 mm. (av. 0.4186 mm.); cornicles, 0.221 to 0.255 mm. 
(av. 0.2401 mm.); caiida, 0.15 mm.; hind tarsi, 0.12 to 0.135 mm. 
(av. 0.1275 mm.). 

Alate viviparous female. — Prevailing color pale to apple green. 
Head, antennae, thorax, marginal spots on abdomen, cornicles, tip of 
Cauda, femora, and tarsi all black. Antennae (fig. 289, 290) with the 
usual primary sensoria on V and VI and the usual accessory sensoria 
on VI. IV without sensoi'ia and III with from 6 to 11 fairly large 
circular sccondarj- sensoria, the usual number being 8 (fig. 290). In 
this character it differs most markedly from the Main specimens, 
which have from 12 to 18 sensoria on III and from none to several 
on IV. The antennae are slightly shorter than the body although 
practically of the same length. Ill is the longest segment, closely 
followed by the spur, then by IV, V., VI, I and II. Ill and the spur 
are subequal, or either one or the other may be slightly the longer. 
In Patch's drawing V is a little longer than IV. In the California 
specimen IV is always slightly the longer of the two. In all the 
California specimens the antennal segments are all a little shorter 
than in the Maine material. Lateral tubercles are present on the pro- 
thorax ; they are always present on the seventh abdominal segment, 
and may be present on any of the first few segments of the abdomen 
as well. In one case they were observed on the second and seventh 
segments, in another on the second, third, and seventh, in still another 
on the fourth, fifth, and seventh, and in a fourth case on the first, 
second, third, fourth, and seventh segments (fig. 292). The wings 
and venation are normal, with the second branch of the cubitus arising 
nearer to the tip of the wing than to the base of the first branch (fig. 
291 ) . However, it is not quite so close to the wing tip as in the Maine 
specimens. The cornicles (fig. 292) are long and cylindrical. They 
are equal to or slightly shorter than V, and from one and one-half to 
two times as long as the hind tarsi. The cauda (fig. 292) is more or 
less ensiform, about one-half as long as the cornicles, reaching to the 
tip of the cornicles, and subequal to or slightlj- shorter than the hind 
tarsi. 

Measurements (of specimens mounted in Canadian balsam) : Body 
length, 1.53 to 1.65 mm. (av. 1.585 mm.) ; width of thorax 0.697 to 
0.765 mm. (av. 0.731 mm.), antennae total, 1.568 mm.; I, 0.068 to 
0.085 mm. (av. 0.0765 mm.) ; II, 0.051 mm.; Ill, 0.331 to 0.408 mm. 
(av. 0.3644 mm.) ; IV, 0.238 to 0.289 mm. (av. 0.2817 mm.) ; V, 0.221 
to 0.247 mm. (av. 0.2295 mm.) ; VI base, 0.085 to 0.111 mm. (av. 



100 MISCELLANEOUS STUDIES 

0.1015 mm.) ; VI spur, 0.391 mm.; cornicles, 0.204 to 0.2-46 mm. (av. 
0.2179 mm.) ; cauda, 0.103 to 0.119 mm. (av. 0.1084 mm.) ; hind tarsi, 
0.136 mm. 

118. Aphis cooki Essig 

Figures 212 to 214 

Essig, Pom. Jour. Eut., vol. 2, p. 323, 1910. Aphis gossypii Glover (desc). 
Essig, Pom. Jour. Eut., vol. 3, p. 587, 1911 (orig. desc). 

Record. — Citrus sp., Pomona (Essig). 

In 1909, C. H. Varj', county horticultural inspector in Pomona, 
found a few orange trees heavily infested with this aphid. Prompt 
control measures were taken and since then it has never again been 
observed. Essig first tliought it to be Aphis (jossijpii Glover and de- 
scribed it under that name. Later, however, he found it to be an 
undescribed species, so named it Aphis cooki n.sp. after Dr. A. J. Cook. 

119. Aphis cornifoliae Fitch 

Fitch, Cat. Homop. N. Y., p. 65, 18,51 (orig. desc). 

Records. — Cornus pu&esccHS, Sanicula menziesii ; San Francisco Bay region 
(Davidson). 

A species comparing very favorably with this has been taken bj' 
Davidson a number of times in the San Francisco Bay region. The 
fall and winter is spent on dogwood, the summer on gambleweed. 
Davidson writes as follows : 

This aphid [from «S'a»!c«7a] certainly appears to be very close to what I have 
called (after Gillette) ctirnifoliac. Moreover, I have noticed that the two plants, 
dogwood and Sanicula, frecjueutly grow near each other and that there appeared 
to be a migration of alates from the former just about the time there was a 
migration of the alates to the latter. 

This migration took place the latter jiart of April in 1916. 



120. Aphis crataegifolii Fitch 

Fitch, Cat. Homop. N. Y., p. 66, 1851 (orig. desc). 
Sanborn, Kan. Univ. Sci. Bull. 3, p. 53, 1904 (desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). 

Record. — Crataegus oxycantha; San Jose, Palo Alto (Davidson). 

This lias been reported more or less abundant on hawthorne in the 
San Francisco Bay region. According to A. C. Baker this is a good 
and distinct species and not a synonym of Aphis ponii De Geer, as 
formerly believed. 



A SYNOPSIS OF THE APHIDIDAE 101 

12]. Aphis euonomi Fabr. 

Figures 182, 187, 190. 205 to 207, 23G, 237 

Fabricius, Syst. Eiit., p. 736, 1794 (orig. desc). 

Davidson, Jour. Ecoii. Eut., vol. 2, p. 302, 1909. A. rumicis Linn, (list, in 

part?). 
Essig, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 446, 1915. A. rumicis Linn. 

(list). 

Eecords — AUh-aea rosea, Berkeley, June, 1915; Hijibiscus moscheutos, Berkeley, 
July, 1915: Moiiteiius hoaria, Berkeley, July, 1915; Mesemiryanthemum equilat- 
erale, Stanford University, June, 1915 ; Silyhum marianum, Stanford University, 
July, 1&15: TJrtica holoserica, Menlo Park, San Mateo County, January, 1915: 
Calendula officinale, Orange, February, 1917: Anthemis sp., Pasadena, April, 1917: 
Papaver sp., El Cajon, San Diego County, May, 1916 (Aphis papaveris Fabr.?) : 
Vici^i falta, Stanford University (Davidson), Oxnard (Essig, 1915), Montebello, 
Los Angeles County, December, 1916, Riverside, January to May 1917 (Apliis 
fabac Seop.?): Eumex spp., Palo Alto, January, 1912 (Davidson), Stanford 
University, March. 1912 (Morrison), March, 1915, Ventura County, May, 1917: 
Phascolus spp., Ventura County, May, 1917 (Aphis rumicis Linn.?). 

There ha.s been a great deal of confusion regarding the identity 
of this species of aphid, and as yet its synonomj^ is not worked out 
satisfactorily. The following is offered only provisionally b.v the 
autlior. The eonmion black aphid has usually been considered as 
Aphis riuiiici^s Linn., Aphis euonomi Fabr. being taken as a synonym, 
but according to Gillette, Linnaeus' description calls for an aphid 
"brassy brown in color, and not black according to the popular opin- 
ion; and its food plant should be species of Rumcx." He considers 
the common black species to be Aphis euonomi Fabr., as does Mord- 
wilko in the European form. The author follows these two aphidol- 
ogists in placing Aphis rumicis Linn, of American authors (and later 
European authors) as a synonym of Aphis euonomi Fabr. He (i.e., 
Gillette) writes, "whether or not it is synonymous with rumicis we 
are not certain, but we very much doubt this being the case." As 
long ago as 1894, Osborn and Sirrine (Iowa Agr. Sta., Bull. 26, p. 
904, 1894) proved that the species which wintered in Iowa on 
Euoni/mMS migrated to Rumex and other plants in the summer. In 
California the author has been unable to find it at any time vipon 
Euonynius, although this is a very common ornamental plant, especi- 
ally in the vicinity of Riverside. This ma\' be due, however, to the 
mild winter climate of southern California, which permits plant lice to 
live throughout the winter, thus not necessitating the laying of eggs. 
Concerning the identity of the California species the author believes 
the form described briefly below to be Aphis euonomi Fabr. The 



102 MISCELLANEOUS STUDIES 

one following is probably the same species, and is the one described 
as Aphis papavcris by Fabricius. The species from Vicia faba is 
probably the species described as Aphis fahae Scop., which may be 
synonymous with Aphis euonomi Fabr., but again may not be. The 
author tried a few transfer tests this spring (1917) with the form 
from Vicia, attempting to colonize it on Hedera helix and on Rumex 
spp., with negative results. Of course, this does not prove that it will 
not colonize on these plants, although tlie author has come to the conclu- 
sion that the Hedera species is entirely different, being Aphis hederae 
Kalt. Dr. Patch" in her interesting paper on aphid ecology makes 
the following statement regarding migration tests, which, it seems to 
the author, it is well to remember when making such tests : 

If an investigator fails in one hundred attempts to colonize thistle with 
migrants from plum, that will not be a safe reason for him to conclude that he is 
not working with Aphis cardui, or that this thistle aphid has nothing to do with 
the leaf deformations of the plum iu the spring. It has been my experience that 
negative data with a'phids under such conditions are just no data at all. If the 
structural characters are such as warrant the migration test in the first place, they 
warrant a patient continuation even in the face of repeated failures. 

On the other hand (and this is a most encouraging and stimulating circum- 
stance in connection with aphid migration tests), a single success goes a long way 
to prove the case. Barring complications, a single success is enough, and repe- 
titions and verifications are needed only as safeguards in that respect. 

The third description is from specimens taken on Rumex spp. and 
although slightly different from the one considered as Aphis euotimni 
Fabr., it may be the same, and it may be Aphis runiicis Linn., but of 
this the author is doubtful. 

In the bean fields of Ventura County, this black bean aphis is very 
abundant, and often does considerable damage. In May, 1917, the 
bean plants were just beginning to appear, and as yet were not 
infested with the aphis. However, the native dock was quite heavily 
infested. It seems that the aphis lives over the winter on dock and 
perhaps on other native plants, migrating in the early summer to the 
beans. Here it lives throughout the summer, returning to dock when 
the beans have been harvested and the plants plowed under. Horti- 
cultural Commissioner A. A. Brock, of Ventura County, places great 
hope in the efficiency of Hippodamia convergens Guerin as a con- 
trolling factor. In the spring of 1917 he collected a vast number of 
these ladybird beetles in Sespe Canyon and turned them loose in the 
bean fields just as the aphids were beginning to appear. At the 
present time the results are unknown. 



18 Patch, Edith M., Concerning problems in Aphid ecology, Jour. Econ. Ent., 
vol. 9, pp. 44-51, 1917. 



A SYNOPSIS OF THE APHIDIDAE 103 

The following brief description was made from specimens col- 
lected from the first six host plants listed above, and is the one con- 
sidered as Aphis euonomi Fabr. 

Alate viviparous female. — Color apparently black, but on close 
examination it seems that the ground color is a very dark brown, 
covered with a blackish tinge, with the following parts decidedly 
black: head, antennae, thoracic lobes, marginal spots and transverse 
bands on the abdomen, coi"nicles, tarsi, coxae, tips of tibiae, and apical 
one-half to two-thirds of the middle and hind femora. The tibiae and 
fore femora are pale, appearing whitish in life. The antennae are 
shorter than the body, III being the longest segment, followed closely 
by VI spur. In one case VI spur was slightly longer than III and 
in another equal to III. In all other specimens III was the longer 
segment. IV and V are subequal, V usually being slightly the 
shorter. There are from eleven to twenty-one secondary sensoria on 
III, of irregular size. These are .scattered along the whole length of 
the segment, the distal five or six being in a more or less even line. 
The usual number is about twelve to fourteen. The number of 
secondary sensoria on IV range from none to seven, the modal number 
being two. In one specimen only were sensoria absent from IV ; in 
another, one antenna had seven, the other having two, while in a 
third, one antenna had five, the other six. When there are more than 
two or three sensoria, they are all quite small, and can be clearly 
distinguished only by the higher power of a microscope. Two is the 
usual number, being located about the middle of the segment. V is 
usually without secondary sensoria, the primary sensorium being 
always present, however. lu one specimen the antennae had one or 
two very small secondary sensoria on V, and in another specimen one 
antenna had one small sensorium, the other none. The usual primary 
and accessory sensoria are present on VI base. Lateral abdominal 
tubercles are always present on the seventh segment, usually on the 
first, and often on the second, third, fourth, or fifth. There are 
always at least three pair of these tubercles, and oftentimes more. 
One specimen had tubercles on the first, second, third, fourth, and 
seventh segments. The cornicles are black, imbricated, and taper 
noticeably from base to apex. They are quite constant in length, the 
variation being not more than 0.05 mm. in all the specimens examined. 
They are about half as long again as the hind tarsi. The cauda is 
concolorous with the abdomen, short and conical or ensifonn, and 
subequal in length to the hind tarsi. The wings are normal, with the 
typical Aphis venation. 



104 MISCELLANEOUS STCVIES 

Measurements: Body length, 1.53 to 1.989 mm. (av. 1.74 mm.); 
width of thorax, 0.68 to 0.918 mm. (av. 0.765 mm.) ; antennae total, 
1.122 to 1.36 mm. (av. 1.272 mm.) ; III. 0.289 to 0.425 m.m (av. 0.3648 
mm.) ; IV, 0.1955 to 0.272 mm. (av. 0.2266 mm.) ; V, 0.187 to 0.221 
mm. (av. 0.1885 mm.) ; VI, base 0.102 to 0.136 mm. (av. 0.1119 nun.) ; 
VI, spur 0.289 to 0.357 mm. (av. 0.3145 mm.) ; cornicles, 0.1785 to 
0.221 mm. (av. 0.2118 mm.) ; cauda, 0.136 to 0.162 mm. (av. 0.14875 
mm.) ; hind tarsus, 0.136 to 0.152 mm. (av. 0.1372 mm.). 

Specimens taken by the author in May, 1916, on Papaver sp. (cul- 
tivated poppy) near El Cajon, San Diego County, seem to liim to be 
Aphis papaveris Fabr. (Clenera Insectorum. p. 303, 1717), and prob- 
ably' are the same as the above species, although they may be different. 
There are from thirteen to fifteen irregular seeondai-y sensoria on III 
as above, but IV and V are without secondarj- sensoria, with one 
exception, in whicli there was one small sensoriuin near the middle of 
IV. The eauda is ecpial to the hind tarsi, tlie cornicles being longer, 
and about the same comparative length as above. The third antennal 
segment appears to be longer in comparison than above in some speci- 
mens. Lateral abdominal tubercles are present on the first, third, and 
seventh abdominal segments. 

Measurements: Body length, 1.486 to 1.908 nun. (av. 1.711 mm.) ; 
width of thorax, 0.595 to 0.765 mm. (av. 0.68 mm.) ; antennae total, 
1.224 to 1.343 mm. (av. 1.2878 mm.) ; III, 0.323 to 0.374 mm. (av. 
0.3536 mm.) ; IV, 0.2125 to 0.22 mm. (av. 0.2193 mm.) ; V, 0.187 to 
0.204 mm. (av. 0.2024 mm.) ; VI, base 0.102 to 0.119 mm. (av. 0.1054 
mm.) ; VI, spur 0.255 to 0.34 mm. (av. 0.2992 mm.) ; cornicles, 0.187 
to 0.221 mm. (av. 0.204 mm.) ; eauda. 0.136 to 0.153 ram. (av. 0.142 
mm.) ; hind tarsus, 0.119 mm. 

Specimens taken by the author near Montebello, Los Angeles 
County, in December, 1916, and in Riverside from January to May, 
1917, on Vicia faha seem to be somewhat different from the fore- 
going, yet are very nearly identical. Gillette considers that they 
might possibly be Aphis fabac Scop., which may or may not be 
synonymous with Aphis eumiomi Fabr. Superficially, the coloring 
seems to be the same, although on close observation it appears to be 
a very' dark green in ground color, covered with a blackish tinge. The 
legs are colored as above, however. 

Specimens from Rume.r appear to have considerably more brown 
in the ground color than the preceding varieties. Secondary sensoria 
are located as follows: III, 14 to 24 (av. 18) ; IV, 4 to 7 (av. 5) ; V, 



A SYNOPSIS OF THE APHIDIDAE 105 

I to 4 (av. 3). Lateral abdominal tubercles could be found only on 
the first and seventh segments. 

Alate viviparous female. — Measurements: Body lengtli, 1.768 to 
2.142 mm. (av. 1.942 mm.) ; width of thorax, 0.782 to 1.054 mm. 
(av. 0.918 mm.) ; antennae total, 1.445 to 1.581 mm. (av. 1.496 mm.) ; 
III, 0.357 to 0.408 unu. (av. 0.394 mm.); IV, 0.255 to 0.323 mm. 
(av. 0.286 mm.) ; V, 0.204 to 0.255 mm. (av. 0.233 mm.) ; VI, base 
0.136 to 0.153 mm. (av. 0.139 mm.); VI, spur 0.289 to 0.323 mm. 
(av. 0.306 iimi.) ; cornicles, 0.187 to 0.255 mm. (av. 0.219 mm.) ; cauda, 
0.136 to 0.17 mm. (av. 0.153 mm.) ; hind tarsus, 0.119 to 0.153 mm. 
(av. 0.147 mm.). 

Apterous viviparous female. — Measurements : Body length, 2.278 to 
2.448 mm. (av. 2.3403 mm.) ; antennae total, 1.309 to 1.598 mm. 
(av. 1.4382 mm.); Ill, 0.306 to 0.408 mm. (av. 0.3502 mm.); IV, 
0.221 to 0.306 mm. (av. 0.2618 mm.) ; V, 0.206 to 0.255 mm. (av. 0.238 
mm.) ; VI, ba.se 0.119 to 0.17 mm. (av. 0.1394 mm.) ; VI, spur 0.289 to 
0.34 mm. (av. 0.306 mm.) ; cauda, 0.17 to 0.204 mm. (av. 0.187 mm.) ; 
cornicle, 0.255 to 0.323 mm. (av. 0.289 mm.); hind tarsus, 0.153 to 
0.17 mm. (av. 0.167 mm.). 

122. Aphis frigidae Oestluiul 

Oestlund, Geol. Nat. Hist. Snrv. Minn., vol. U, p. 46, 1886 (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 7, p. 132, 1913 (desc. stem mother). 

Eecords. — Artemisia californica; Walnut Creek, Contra Costa County (David- 
son). 

In company with Macrosiphum artemisiae (Fonse.) this species is 
found on sagebrush in the San Francisco Bay region. Wilson reports 
it from Oregon, so probably it is distributed along the coast from the 
bay north. In the course of observations in southern California 
during a period of two j^ears the author has been unable to find any 
aphids infesting sagebrush. 

123. Aphis gossypii Glover 
Figures 192, 193, 215 

Glover, Pat. Off. Ree., p. 62, 1854 (orig. desc.). 

Clarke, Can. Ent., vol. 35, p. 250, 1903 (list). 

Essig, Pom. Jour. Ent., vol. 1, p. 47, 1909. Aphis citri Ashmead (desc.). 

Essig, Pom. Jour. Ent., vol. 3, p. 590, 1911 (desc). 

Cook, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 65, 1912 (list). 

Carnes, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 398, 1912 (list). 

Weldon, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 597, 1913 (list). 

Davidson, Mon. Bull. Cal. Comm. Hort., vol. 6, p. 65, 1917 (note). 



106 MISCELLANEOUS STUDIES 

Secords. — Cucumis spp. ; Newcastle, Placer County, Watsonville, Santa Cruz 
County (Clarke); Imperial County (Weldon) ; San Diego County, June, 1916: 
Cucurbita spp.; Alpine, San Diego County, June, 1916: Citrus spp.; Santa Paula, 
Claremont (Essig), Acampo, San Joaquin County (Carnes), San Diego, March, 
1916 (E. R. McLean); Whittier, May, 1917: Eeracleum lanatum ; Berkeley, 
March, 1915 (Essig): Begonia; Stanford University, February, 1912 (Morrison), 
Eiverside, January, 1917; Punica granatum, Stanford University, April, 1911 
(Davidson): Seliantlms; Santa Ysabel, San Diego County, May, 1916: Pcrsea 
gratissima ; Avondale, San Diego County, August, 1916; Chrysanthemum; 
Ontario, January, 1917; Esclischoltzia calif ornica ; Ontario, January, 1917: 
Anthemis spp.; Pasadena, AprU, 1917 (R. E. Campbell): Pyrus spp.; Santa 
Cruz County (Volck), Nevada County (Norton). 

The melon or cotton aphis is distributed throughout the state and 
is found on a large number of host plants. On melons it is often a 
considerable pest, particularly in the Imperial Valley. In the apple 
sections of Santa Cruz and Nevada counties it often becomes abundant 
enough upon the young trees to cause considerable damage, according 
to County Horticultural Commissioners Volok and Norton. In San 
Diego County the author found an infestation on young avocado trees 
which was very severe. Oftentimes it becomes quite abundant in 
nurseries and greenhouses. 

124. Aphis hederae Kalt. 

Kaltenbaeh, Monog. d. Pflanzenlause, p. 89, 1843 (orig. dese. ). 

Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909. A. rumi-cis Linn, (list in 

part). 
Essig, Pom. Jour. Ent, vol. 2, p. 335, 1910 (desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. A. immicis Linn. (list). 

Becords. — Hedcra helix; Stanford University (Davidson), March, 1912 (Mor- 
rison); Claremont, Los Angeles County (Essig) ; San Jose, May, 1911 (Davidson, 
Morrison); Oakland, November, 1916 (Davidson); Berkeley, April, 1915; Lemon 
Grove, San Diego County, March, 1916; Riverside, October, 1916: Chcnopodium 
sp., Walnut Creek, Contra Costa County, May, 1915 (Davidson). 

Throughout the San Francisco Bay region and southern Califor- 
nia a small dark brown to black aphid is often found in colonies on 
the tender shoots of English ivy. Essig described it as Aphis hederae 
Kalt., but later it was believed to be Aphis rumici-s Linn. {A. euonami 
Fabr.). However, a careful study of a large series of specimens of 
this aphid from ivy and of A. euonmni Fabr. from a number of dif- 
ferent host plants has convinced the author that they are distinct. 
Gillette is of the same opinion. Consequently the species from ivy 
in California is Aphis hederae Kalt. In the author's collection there 
is a specimen from Chenopodium sp. taken by Davidson that appears 
to be the same species. The most noticeable difference between this 



A SYNOPSIS OF THE APHIDIDAE 107 

and Aphis cucinumi Fabr. is iu the length of the cornicles, which are 
very much longer in this species. Measurements of specimens of the 
alates from Oakland, Walnnt Creek, San Jose, and Riverside are 
herewith given : 

ileasurt'nients : Body length, 1.411 to 1.768 mm. (av. 1.621 mm.) ; 
width of thorax, 0.714 to 0.782 mm. (av. 0.748 mm.) ; antennae total, 
1.411 to 1.549 mm. (av. 1.499 min.) ; III, 0.323 to 0.391 mm. (av. 0.365 
mm.) ; IV, 0.272 to 0.323 mm. (av. 0.2914 mm.) ; V, 0.221 to 0.272 mm. 
(av. 0.2518 mm.) ; VI, base 0.119 to 0.136 mm. (av. 0.311 mm.) ; VI, 
spur 0.306 to 0.34 mm. (av. 0.323 mm.) ; cauda, 0.136 mm.; cornicle, 
0.306 to 0.34 mm. (av. 0.3252 mm.) ; third tarsus, 0.119 to 0.136 mm. 
(av. 0.1237 mm.). 

It will be seen that tlie cornicles are considerably more than twice 
as long- as the hind tarsi, in some cases practically tliree times, while 
in A. euonomi Fabr., the.v are scarcely twice as long as the hind tarsi. 
In A. euonomi Fabr. the hind tarsi are longer than the base of VI, 
while the cornicles are shorter than VI spur. In A. hederae Kalt. VI 
spur and the cornicles are subequal or on the average the cornicles are 
very slightly longer, while VI base and the hind tarsi are also sub- 
equal, the tarsi being shorter on the average. The secondary sensoria 
in A. hederae Kalt. are small, irregular in size, and are scattered more 
or less irregularly along III but in a fairly even row along IV and V. 
They appear very much the same as in A. euonomi Fabr. There are 
from thirteen to twenty on III, seventeen being the average; from 
five to nine on IV, seven and eight being the usual number; and 
usually one on V, although in a few cases there appear to be none. 

125. Aphis heraclei Cowen 

Coiven, Hemip. Colo., p. 120, 1895 (orig. desc). 

Essig, Univ. Calif. Publ. Eutom., vol. 1, p. 339, 1917 (list). 

Record. — Heracleum montezznmum ; Berkeley (Essig). 

Recentlj' Essig reported having taken this species on Heracleum 
in Berkeley. The author has specimens from Essig, although he has 
never collected it himself. This is the only report of the species since 
Cowen 's original report and description. 

126. Aphis houghtonensis Troop? 

Troop, Ent. News, vol. 17, p. 59, 190G (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 7, p. 132, 1914 (list). 

Record. — Ribes sanguineum; Contra Costa County (Davidson). 



108 MISCELLANEOUS STUDIES 

Davidson reported a species of Aphis infesting the terminal leaves 
of wild currant in the canj'ons of Contra Costa County. He identified 
it provisionally as this species as he was uncertain. The author is 
unacquainted with it. 



127. Aphis lithospermi Wilson 
Wilson, Trans. Am. Ent. Soc, vol. 41, p. 100, 1915 (orig. desc). 
Becord. — Lithospermum pilosum; California (WUson). 

There is no definite record of this species in California, but it is 
listed here because Wilson added it to a list of the California Aphi- 
didae submitted to him by the author. 



128. Aphis maidis Fitch 

Figures 216 to 218 

Fitch, Insects N. Y., vol. 1, p. 318, 1855 (orig. desc). 
Clarke, Can. Ent., vol. 35, p. 251, 1903 (list). 
Davidson, Jour. Econ. Ent., vol. 5, p. 408, 1912 (list). 

Records. — Corn; Watsonville, Berkeley (Clarke); San Jose (Davidson); Lake- 
side, San Diego County, April, 1916; Chula Vista, San Diego County, August, 
1916: sorghum; Julian, San Diego County, August, 1916 (H. M. Armitage) ; 
Corona, Eiverside County, September, 1916. 

Onlj' oceasionalh' is this corn aphis found in California, where it 
infests the ears and tassels and leaves of corn and some of the sor- 
ghums. Never has it been observed as injurious as is sometimes 
reported from the middle western states. 



129. Aphis malifoliae Fitch 

Figures 248 to 250 

Fitch, Trans. N. Y. State Agr. Soc, vol. 5, p. 14, 1854 (orig. desc). 
Clarke, Can. Ent., vol. 35, p. 252, 1903. Aphis sorbi Kalt. (list). 
Carnes, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 400, 1912. A. sorbi Kalt. 

(list). 
Weldon, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 188, 1914. A. sorbi Kalt. 

(list). 
Baker and Turner, Jour. Agr. Res., vol. 7, pp. 321-343, 1916 (complete 

account). 

Records. — Pyrus malus, P. communis ; Central and northern California; Orange 
County, May, 1917. 



A SYNOPSIS OF THE APHIDIDAE 109 

This is one of the most injurious of our California species of Aphis, 
being found in practically all of the apple-growing regions of tlie 
state, and in most of them necessitating some control measures. It 
has been reported on apple and pear in the following counties : Hum- 
boldt, Orange, Placer, Sacramento, Santa Clara, Shasta, Tehama, 
Nevada, Inyo, Santa Cruz, and Alameda. Probably it is present 
wherever apples are grown, with the exception of the southern Cali- 
fornia districts where it has never been observed. The apple is the 
primarj- host, and only occasionally has it been taken on pear. In 
May, 1917, Roy K. Bishop found it in Orange County, this being the 
first report of it south of the Tehachapi. 

The life histor.y of this Aphis in California is as follows : 
In the fall and early winter the eggs are laid in the crotches of the 
twigs. These hatch in the following spring, the exact time depending 
upon the weather conditions but it is usually as the buds are begin- 
ning to show green, or as they are beginning to open. The author has 
observed the young stem mothers on the young buds of the apple in 
the latter part of March, although he has never been able to find the 
eggs, either those yet unhatched or those from which the stem mothers 
have already hatched. Horticultural Commissioner Weatherby of 
Humboldt County writes that he has found the eggs hatching as early 
as February 24. He goes on to state that the eggs of Aphis pomi 
De Geer do not hatch until considerably later. Horticultural Com- 
missioner Norton of Nevada County has made the following observa- 
tions : 

The eggs of Aphis sorbi [inalifoliae] are laid on the buds, or sometimes on 
the spurs close to the buds. At first they are hard to see as they are small and 
light green, but later they turn to a shiny black, when they can be more readily 
detected. The young aphids hatch as soon as the buds begin to swell, which time 
varies with the season. I have found them sometimes as early as the first of 
March and at other times as late as the middle of April. 

The stem mothei*s feed upon the plant juices through the buds, 
sometimes appearing on the outer surface of the buds and at other 
times crawling down into the unfolding leaves, as is the ca.se with 
Aphis pomi De Geer. In a few weeks these are mature and begin to 
deposit live young. All of this second generation are apterous females 
so far as the author has been able to observe. On April 12, 1915, he 
found several colonies of these aphids in the apple orchard at Stanford 
University, each colony consisting of a stem mother and several young 
apterous viviparous females. These females mature in a few weeks 



110 MISCELLANEOUS STUDIES 

and a third generation is begun. The most usual place to find the 
second and third generations is in the curled terminal leaves of the 
plant. These leaves are curled very similarly to those by the green 
apple aphis {Aphis pomi De Geer), but they are curled a great deal 
tighter. Winged females may appear in this third generation, but 
it is most usual to find them in the fourth. Horticultural Commis- 
sioner Volck of Santa Cruz County states that he has counted four 
generations before the summer migration. During May, 1915, the 
author collected many colonies of this Aphis and placed them in vials 
in the laboratory. Many others he attempted to colonize on some 
apple seedlings. Owing to various causes he was unable to make any 
successful colonizations on the apple trees, one of the chief causes 
being the destructive work of coccinellid larvae. Also during the 
first few days of June he was forced to be absent from town and on 
his return found that the gardener had "cleaned" the trees, for 
"they were all covered with lice." Until May 25 no alate females 
had been found, but on that date two appeared in the laboratory. On 
May 10, 1917, alates were found in Orange County. 

These alate females of the fourth (perhaps sometimes they appear 
in the third) generation migrate from the apple to some unknown 
host. At Stanford University in 1915 the migration began about 
the first of June and continued for some two or three weeks. On 
June 20 only two or three colonies, each consisting of but a very few 
individuals, were found where a month before there had been literally 
hundreds. The curled leaves still hung on the trees and in each 
curled leaf the moulted skins of the aphid were abundant. From 
Commissioner Norton of Nevada County comes the statement that he 
has known the migrants "to leave the trees as early as the middle 
of J\ine, but the migration usually takes place between the first and 
the fifteenth of Julj-. Where they go I have never been able to find 
out, as I have never observed them on any other host plant." 

According to 0. E. Bremner, Horticultural Commissioner of 
Sonoma County, the migration takes place there during June. This 
is the same a-s in Santa Clara County. In Orange County in 1917 
the alate females appeared about the first of May. Migration began 
almost immediately and continued for two or three weeks. By May 24 
only a very few aphids remained. This is fully a month earlier than 
migration takes place north of the Tehachapi. Incidentally the spring 
of 1917 was exceedingly cool and the summer very late. In normal 
years one would expect the aphids to leave the apple two or three 
weeks earlier. 



A SYNOPSIS OF THE APHIDIDAE 111 

Tlie summer host plant of this aphid is as yet unknown in Cali- 
fornia. During June, 1915, the author spent many hours in search 
of this host plant, hut to no avail. He examined every kind of plant 
within two or three hundred yards of the apple orchard at Stanford 
University, but on none was he able to find any aphid that could pos- 
sibly be the summer form of Aphis malifolme Fitch. Bremner reports 
having found isolated individuals on pigweed (Amaranthus retro- 
flexus) in Sonoma County, but believes this to be accidental for he has 
never observed them to deposit young on this plant. Davidson writes 
that he has been able to colonize them in the laboratory on the leaves 
of plantain {Plantago spp.), in fact has been able to have them repro- 
duce in such large numbers as to kill the plants. On May 28, 1915, 
the author placed two alate females from apple leaves on each of two 
specimens of Plantago hirteUa under bell jars in the laboratory at 
Stanford University. On returning to towai on June 10 he found that 
the plants were in a dying condition, owing to a lack of proper care 
during his absence. However, he found many young lice present, all 
of which were alive and feeding. The adult alate females had already 
died. By June 16 the lice had moulted once, but then the plants were 
practically dead. He left Stanford within a few days not to return, 
so was unable to begin fresh experiments along this line. In his search 
for the alates in the field he was particularly careful to examine 
closely every plantain plant in the vicinity, but could find no trace of 
this aphid on them. Davidson also reports the same lack of success. 
Consequently, although the alates will deposit young on plaintain 
in the laboratory it cannot very well be the natural summer host in 
this state. Baker and Turner have proven that Plantago lancrolata 
is the summer host in Virginia. W. H. Britain has observed a definite 
migration to plaintain in Nova Scotia (Proe. Ent. Soc. Nova Scotia, 
vol. 1, pp. 16-30, 1915). Incidentally he has been able to breed it 
throughout the summer on apple. In Orange County, in the vicinity 
of the known infestations, the author was unable to find any plaintain 
whatsoever. On inquiring of Roy K. Bishop, the county horticultural 
commissioner, it was learned that plaintain is very scarce in that 
county, except very near to the coast, and that it is exceedingly doubt- 
ful if there is any in the vicinity of the known aphid infestations. 

The fall migrants begin to return to the apple some time during 
the fall and deposit living males and females. From Nevada County 
comes the report that the migrants return to the apple "between the 
twentieth of September and the first of October. " Davidson has taken 
the oviparous females and the alate males on December 5 (1912) at 



112 MISCELLANEOUS STUDIES 

Sebastopol ; Morrison has taken the sexes at Stanford University on 
December 16 (1910) ; Moznette of the Oregon station has taken the 
migrants as late as the middle of November at Corvallis, Oregon. 
Consequently, egg laying probably occurs from the middle of October 
well into December in the various parts of California. Commissioner 
Norton states: "The first eggs that I have seen were observed about 
the fifteenth of October. However, they continue egg laying, in 
favorable years, well along into November." 

The injury caused by this aphid is done entirely in the spring of 
the year, before the summer migration, and consists in the curling of 
the terminal leaves. The colonies are found usually in the leaves 
surrounding a cluster of apples, and although most of the feeding is 
on the leaves themselves oftentimes they feed upon the fruit. In 
such a case the fruit (according to Weldon, "Apple Growing in Cali- 
fornia," Mon. Bull. Cal. Comm. Hort., p. 86, 1915) "is injured to 
such an extent that it becomes stunted and not only fails to mature, 
but is distorted so badly that the variety may not be recognizable." 
In Nevada County, Commissioner Norton reports : ' ' The purple aphis 
unless controlled lessens tlie apple crop from ten to fifteen per cent. 
This is a higher percentage, undoubtedly, than is common throughout 
the state, but it shows how serious the pest may be. 



130. Aphis marutae Oestlund 

Figures 293 to 299 

Oestlund, Minn. Geol. Nat. Hist. Surv., vol. 14, p. 40, 1886 (orig. desc.). 

Mecords. — Silybum marianum; Gros.smont, San Diego County, April, 1916: 
Centaurea melitensis ; El Cajon, San Diego County, May, 1916. 

In April, 1916, the author observed a small aphid on milk thistle 
near Grossmont, San Diego County, and later on tacalote in the 
El Cajon Valley. It infested the smaller leaves, the leaf petioles, and 
the base of the flowers. Large numbers of ants were in attendance, 
but it was preyed upon extensively by the larvae and adults of Cocci- 
nella californica. A considerable number of adults of LyslpMehus 
testaceipes Cresson were reared from colonies of this aphid. Being 
unknown to the author specimens were sent to J. J. Davis and E. 0. 
Essig, both of whom determined the species to be Aphis marutae Oest- 
lund. Inasmuch as Oestlund 's descriptions are the only ones avail- 
able, a brief description is given below of specimens taken May 1, 
1916, on Silyhum marmnum in San Diego County. 



A SYNOPSIS OF TEE APHIDIDAE 113 

Alatc viviparous female. — Prevailiug color pale to olive green. 
Head and prothorax dark olive green, thoracic lobes almost black. 
Abdomen pale green with marginal spots and patch on dorsum dusky. 
Legs pale except tarsi, apex of tibiae, and apical two-thirds of femora. 
Antennae, cornicles, and cauda dusky. Beak pale at base and dusky 
at tip. 

Head (fig. 293) not quite as long as broad, with a prominent 
tubercle at apex of front and small but distinct projections from head 
on inner side of first antennal .segments. Antennae about same lengtli 
as body or slightly longer or slightly shorter (figs. 294-295). Ill and 
the spur are about equal or III slightly longer, never shorter than 
spur. IV about one-half as long as III. V either shorter or equal to 
IV. VI shorter than V and about one-third as long as spur. I and II 
subequal and slightl.y shorter than VI. The usual primary sensoria 
are present on V and VI and the accessory sensoria on VI. Ill is 
tuberculate and IV is slightly so. IV has from two to six small, 
circular secondary sensoria and III from eleven to fifteen irregularly 
placed (fig. 294). The beak reaches considerably beyond the second 
coxae, in some cases almost to the third. 

The prothorax is without lateral tubercles. The wings are about 
twice as long as the body with normal venation. The stigmal vein is 
curved its entire length, the second branch of the cubitus arises about 
midway between the tip of the wing and the base of the first branch. 

The abdomen is without lateral tubercles in so far as the author 
can discern. The cornicles (fig. 299) are short and taper slightly 
from base to apex. They are about equal in length to the third tarsi, 
are almost one-half as wide at base as long, and about one-third 
as wide at apex as long. The cauda (fig. 298) is shoi't and blunt 
(conical) and about two-thirds as long as the cornicles. The anal 
plate is half-moon-shaped and dusky at its distal edge. 

Measurements (of specimens in Canada balsam) : Body length, 
0.918 to 1.02 mm. (av. 0.9248 mm.) ; width (thorax), 0.34 to 0.442 mm. 
(av. 0.4082 mm.) ; antennae total, 0.885 to 1.02 mm. (av. 0.942 mm.) ; 
I, 0.034 to 0.051 mm. (av. 0.037 mm.) ; II, 0.034 to 0.051 mm. (av. 
0.048 mm.) ; III, 0.225 to 0.2975 mm. (av. 0.2601 mm.) ; IV, 0.117 to 
0.17 mm. (av. 0.152 mm.) ; V, 0.1105 to 0.136 mm. (av. 0.1346 mm.) ; 
VI, 0.068 to 0.102 mm. (av. 0.0833 mm.) ; spur, 0.204 to 0.272 mm. 
(av. 0.2295 mm.) ; cornicles 0.0850 to 0.119 mm. (av. 0.0978 mm.) ; 
cauda, 0.0595 to 0.068 mm. (av. 0.0624 mm.) ; hind tarsi, 0.085 to 
0.102 mm. (av. 0.0901 mm.) ; wing length, 1.921 to 1.955 mm. (av. 
1.928 mm.) ; wing width, 0.661 mm.; wing expansion, 4.556 mm. 



114 MISCELLANEOUS STUDIES 

Apterous viviparous female. — The apterae are quite similar to the 
alates except that the thorax is not dark, and that the second, third, 
and basal three-fourths of the fourth antennal segments are pale. 
There are no secondary sensoria (fig. 296) and no lateral tubercles 
on prothorax and abdomen (fig. 297). The individuals are slightlj^ 
larger and the proportions of the antennal segments differ slightly 
from the alates. The measurements of specimens mounted in Canada 
balsam are as follows : 

Measurements: Body length, 1.00 to 1.04 mm. (av. 1.026 ram.); 
width (abdomen), 0.595 to 0.629 mm. (av. 0.6064 mm.) ; antennae 
total, 0.561 to 0.697 mm. (av. 0.6151 mm.) • III, 0.102 to 0.136 mm. 
(av. 0.1218 mm.): IV. 0.0765 to 0.1105 mm. (av. 0.0906 mm.); V, 
0.068 to 0.085 mm. (av. 0.0765 mm.) ; VI, 0.595 to 0.0765 mm. (av. 
0.068 mm.) : spur, 0.1615 to 0.1785 nnn. (av. 0.1711 mm.) ; cornicles, 
0.0765 to 0.11 mm. (av. 0.0935 mm.) ; cauda, 0.0595 mm.; hind tarsi, 
0.102 mm. (Description from nine specimens of apterae). It will 
be noticed that in the apterae the antennae are but about two-thirds 
as long as the body, while in the alates they are almost as long as the 
body. Furthermore, in the apterae the spur of the sixth antennal 
segment is always longer than III while in the alates it is equal to III 
at the most, and in many cases shorter. 



131. Aphis medicaginis Koeh 

Figure 189 

Koch, Die Pflanzenlause, p. 94, 1854 (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909 (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910 (list). 
Essig, Pom. Jour. Ent., vol. 3, p. 527, 1911 (desc). 

Becords. — Medicago hispida; Stanford University (Davidson), April, 1914 
(K. W. Haegele) : Astragalus leucopsis; Nordhoff, Ventura County (Essig) : Vicia 
faha, lima bean, Pasadena (E. E. Campbell). 

This small dark Aphis has been found occasionally in California, 
particularly on alfalfa and beans. Such other plants as loco weed, 
licorice, sagebrush, locust, and others are said to be hosts. The author 
has never collected it himself, but lias had access to specimens taken 
by Essig, Haegele, and Campbell. Davidson has reared the braconid 
fly, Lysipheebus testaceipes Cresson, from this aphid. 



A SYNOPSIS OF THE APHIDIDAE 115 



132. Aphis middletonii Thomas 

Figures 219, 220 

Thomas, 8th Ann. Rep. 111. St. Ent., p. 99, 1S79 (orig. desc). 

Bccords. — AmarantJn^s rctroflcxus; Santa Paula, August, 1911 (Essig) : Ran- 
tinculus calif orniciis; Julian, Sau Diego County, June, 1916: Hemuonia rudis; 
Stanford University, 1916 (Ferris) : Hclmnthit.s unituui; Riverside, September, 
1916. 

In the fall of the year this species is rather eommou on the roots 
of various plants in California. The individuals are small green 
aphids, covered with a slight pulvei'ulence. The^' are very similar 
to Aphis maidis-radicis Forbes, with which they have often been con- 
fused, and differ particularly in the presence of seeondarj- sensoria 
on the fourth antennal segment of the apterae. Below are a few 
descriptive notes taken from specimens mounted in balsam, collected 
in 1916 in Julian and Riverside, and in 1911 near Santa Paula: 

Alate viviparous female. — Greenish, pruiuose. Head, antennae, 
tliorax, marginal spots on abdomen, cornicles, cauda, apical one-half 
femora, apices tibiae, tarsi, and apex of beak, black. Antennae reach 
to the base of the second abdominal segment ; III being the longest 
segment, followed by VI spur. IV and V are subequal, VI base 
slightly shorter. Tlie usual primary and accessory sensoria are pres- 
ent. Secondary sensoria occur on III and IV (fig. 220). There are 
nine to twelve on III, and one to four on IV. The average numbers 
are eight and two respectively. The beak reaches to the third coxae. 
Prominent lateral tubercles are present on the first and seventh 
abdominal segments, as well as on the prothorax. The cornicles are 
short and taper slightly toward the apex. They are subequal in 
length to the hind tarsi, and very slightly larger than the cauda. The 
wings are normal, with the second branch of the third discoidal arising 
nearer to the apex of the wing than to the base of the first branch. 

Measurements: Bod.v length, 1.65 to 1.7 mm. (av. 1.674 mm.); 
width of tliorax, 0.561 mm.; antennae total, 0.816 to 0.918 mm. (av. 
0.884 mm.) ; III, 0.204 to 0.255 mm. (av. 0.2338 mm.) ; IV, 0.11 to 
0.119 mm. (av. 0.1169 mm.) ; V, 0.11 to 0.136 mm. (av. 0.1275 mm.) ; 
VI, base 0.085 to 0.102 mm. (av. 0.0986 mm.) ; VI, spur 0.204 mm.; 
cauda, 0.102 mm.; cornicles, 0.1275 to 0.136 mm. (av. 0.1332 mm.) ; 
hind tarsus, 0.119 to 0.136 mm. (av. 0.1303 mm.) ; wing length, 1.904 
to 2.38 mm. (av. 2.159 mm.); width, 0.731 to 0.85 mm. (av. 0.815 
mm.) ; expansion, 4.3 to 5.1 mm. (av. 4.717 mm.). 



116 MISCELLANEOUS STUDIES 

Aptermis viviparous female. — These are very similar to the alate 
females, only slightly larger. The antennae are duskj^ throughout 
except the base of III. They reach to the base of the first abdominal 
segment. Ill is the longest segment. VI spur is next, being about 
two-thirds a.s long. IV, V, and VI base are subequal, with V some- 
what shorter than the others. The usual primarj- and accessory seu- 
soria are present on V and VI. Ill has two or three small secondary 
sensoria located in the apical one-third of the segment. IV has from 
one to three in the apical one-half. The prothorax and the first and 
seventh abdominal segments each have a pair of conspicuous lateral 
tubercles. The cornicles are black and somewhat larger than in the 
alates, being slightly longer than the hind tarsi. The cauda is a 
little shorter than the hind tarsi. 

Measurements: Body length, 1.632 to 1.785 mm. (av. 1.708 mm.) ; 
width of tliorax, 0.748 to 0.85 mm. (av. 0.799 mm.) ; antennae total, 
0.867 to 0.969 mm. (av. 0.9265 mm.) ; III, 0.2465 to 0.289 mm. (av. 
0.2635 mm.) ; IV, 0.102 to 0.136 mm. (av. 0.119 mm.) ; V, 0.102 to 
0.119 mm. (av. 0.1105 mm.) ; VI, base 0.119 mm.; VI, spur 0.1615 to 
0.187 mm. (av. 0.17 mm.); cornicles, 0.153 to 0.17 mm. (av. 0.1615 
mm.) ; Cauda 0.119 mm. ; hind tarsus, 0.136 mm. 



133. Aphis mori Clarke 
Clarke, Can. Ent., vol. 35, p. 2.51, 1903 (orig. desc). 
Record. — Moms sp., Berkeley (Clarke). 

This is a rather doubtful species, described by Clarke from speci- 
mens taken on mulberry in Berkeley. Since the original description 
it has never again been observed. 



134. Aphis neomexicana Ckll. var. pacifica Dvdn. 

Figures 300, 302 

Davidson, Jour. Econ. Ent., vol. 10, p. 293, 1917 (orig. desc. var.). 
Hecords. — Eibes rubrum ; Walnut Creek, Contra Costa County, and San Jose 
(Davidson). 

Davidson described this variety from .specimens found curling the 
leaves of cultivated red currant in Walnut Creek in June, 1915. 
What he takes to be the same species he had already collected in San 
Jose in May, 1912. The author has specimens from him, but has never 
collected any himself. 



A SYNOPSIS OF THE APHIDIDAE 117 

135. Aphis nerii Fonse. 

Figures 221, 222 

Boyer de Fonscolombe, Ann. Eut. Soc. France, vol. 10, p. 167, 1841 (orig. 

desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). 

Davidson, Jour. Eeon. Ent., vol. 3, p. 377, 1910. A. lutescens Monell (list). 
Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911. A. lutescens Monell (list). 
Essig, Pom. Jour. Ent., vol. 3, p. 401, 1911. A. lutescens Monell (desc). 
Essig, Pom. Jour. Ent., vol. 3, p. 530, 1911 (desc.) 
Branigan, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 53, 1915 (list). 

Eecords. — Asclcpias mexicana; Stanford University (Davidson) ; Stanford 
University, October, 1910 (Morrison) ; Penryn, Placer County (Davidson) ; south- 
ern California (Essig); Berkeley, July to September, 1915: Nerium oleander; 
southern California (Essig); Sacramento (Branigan) ; Berkeley, August to Decem- 
ber, 1915; San Diego, 1916. 

In the late .spring, summer, and early fall milkweeds throughout 
the state are often seen to be infested with a bright yellow and black 
aphid. In the fall and early winter this same species is found infest- 
ing oleanders. Where oleanders are present but no milkweeds this 
aphid can be found from spring until winter on the oleander, as 
observed during 1916 in San Diego. 

Heretofore the species on oleander and milkweed have been con- 
sidered as distinct, the former being called A. lutescens Monell, the 
latter A. nerii Ponsc. According to a note from J. J. Davis the 
species on milkweed could not be A. lutescens Monell. Following are 
extracts from his letters concerning this point: 

I am wondering whether you have ever found winged specimens on Asclepias 
that do not bear the black markings at the base of the cornicles. All the speci- 
mens that I have collected and which Mr. Monell has collected in recent years have 
these black markings at the base of the cornicles in the winged forms. However, 
in referring to an old note from Mr. Monell, he says that it would seem hardly 
possible that he could have missed these dark spots if they had been present in 
the specimens from which he drew his description for Aphis lutesceiis, and re- 
marks further that he is not sure that he has ever seen A. lutescens alive since he 
first described it. I am wondering if lutescens is not really asclepiadis of Pass- 
erini and whether our other common species on Asclepias and Nerium is not 
nerii Fonsc. 

During the summer of 1915 the author found this species on 
Asclepias in the Botannical Gardens at the University of California. 
During July and August it was quite abundant; in fact, it was 
especially thick on the stems and undersides of the leaves and blossoms. 
However, in the latter part of Augu.st it seemed to be getting less 



118 MISCELLANEOUS STUDIES 

and less numerous. No sign of parasites was present, and the pre- 
daceons enemies were not more abundant than usual, so a searcli for 
the cause was made. Within fifty feet of the milkweed plants several 
oleanders were found and on them was noticed a large yellow species 
of Aphis. This supposedly was Aphis ncrii Fonsc. In the laboratory 
the author could find no structural difference whatsoever between this 
species and the one on Asclcpias, so he continued"to watch them care- 
fully on the hosts. As the days passed the Asclepias became freer and 
freer of the infestation, while the Nerium became more and more 
heavily infested. This continued through September and into October, 
b}' which time the Asclepias had died down and incidentally no aphids 
were left. The Nerium was very heavily infested then. This was 
taken a.s a good proof that these were the same species. Later Essig 
told tlie author that the summer before (1914) he had made transfer 
tests in the laboratory of specimens from Asclcpias to Nerium and 
that they thrived there and bred well. This fact and the observations 
above mentioned were noted in a letter to Davis. Following is his 



I have your letter relative to Aphis aselepiadis and nerii, and am interested 
in your observations. In 1914, Theobald described a species under the name of 
Aphis nigrepes, which he now places as a variety of aselepiadis. He considers 
nerii as distinct from aselepiadis because the latter lacks the black patches at 
the base of the cornicles. Passerini 's aselepiadis is entirely different from Fitch 's 
Aphis aselepiadis. Fitch's name has priority for, as you will notice, it was 
described in 1851. This being the case, Passerini 's name will have to fall and 
be replaced by Aphis lutescens of Monell, which according to Mr. Monell 's data 
does not bear the black patches around the base of the cornicles. 

This would seem to indicate tliat the California species on Asclepias 
is Aphis nerii Fonsc. and not .1. liifescDis Monell, as brought out by 
Essig 's experiment and by the author's observation. Consequently 
this Californian species is Aphis nerii Fonsc, with Aselepias for its 
summer host and Nerium. for the winter host. 



136. Aphis oenotherae Oestlund 

Oestlund, Minn. Geol. Nat. Hist. Surv., Bull. 4, p. 62, 1887 (orig. desc). 
Clarke, Can. Ent., vol. 35, p. 252, 1903 (list). 

Record. — Oenothera hectiana; Epilobium sp., Berkeley (Clarke). 

In 190.3 Clarke recorded finding tliis species on primrose and 
willow herb in Berkeley. Since then it lias not been observed in Cali- 
fornia. Tlie author has had the opportunity to study specimens from 
Minnesota, taken by A. C. Maxson. 



A SYNOPSIS OF THE APHIDIDAE 119 

137. Aphis oregonensis Wilson 

Wilsou, Traus. Am. Ent. Soc, vol. 41, p. 92, 1915 (orig. desc). 
Record. — Artemisia tridcntata, California (Wilson). 

Wilson stated to the author that lie had taken this .species in 
California although he gave no loealit.y or date records. On the 
strength of his statement it is included among the California aphids. 
The author has never seen specimens of it. 



138. Aphis persicae-niger Smith 

Figures 223, 224 

Smith, Ent. Am., p. 101, 1890 (orig. desc). 

Clarke, Can. Ent., vol. 3.5, p. 2.52, 1903 (list). 

Gillette, Jour. Econ. Ent., vol. 1, p. 308, 1908 (desc). 

Weeks, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 244, 1912 (list). 

Jones, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 318, 1912 (list). 

Carnes, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 399, 1912 (list). 

Wood, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 570, 1913 (list). 

Secords. — Prunus spp. ; throughout California. 

This species is ordinarily found infesting the tender twigs and 
leaves of peach in the spring and early summer. Occasionally it is 
found on nectarine, plum, and cherry. There are two records of its 
occurrence on cherry known to the author; one in San Jose in May, 
1912, by Davidson, and one in El Cajon, San Diego County, in May, 
1916, by the author. Definite reports of its presence on peach come 
from Los Angeles, Placer, Riverside, San Benito, San Bernardino, 
San Diego, Santa Clara, and Tehama counties. In May, 1916, the 
author observed it doing considerable damage to a j^oung peach orchard 
in the El Ca.ion Valley, San Diego County. Many of the twigs and 
some of the larger branches were killed back for several inches, due 
to the ravages of this insect. 

The Hippodaiiila ladybird and the larvae of a syrphid fly were 
abundant and devouring vast numbers of the aphids. However, it is 
not often that this appears abundant enough to cause anj- great 
amount of damage. 

Its life history, although not thoroughly worked out, is interesting. 
The following brief summary is from Essig:'' 

The insect winters over on the roots of the peach trees, where it may also be 
found in the summer. The first aphids appear above ground very early in the 



1' Essig, E. 0., Beneficial and injurious insects of California; ed. 2. Suppl. 
Mon. Bull. Cal. Comm. Hort., vol. 4, pp. 91-92, 1915. 



120 MISCELLANEOUS STUDIES 

spring and begin attacking the tender leaflets, shoots and suckers, usually those 
at the base of the tree or nearest the ground. These first plant lice are all wing- 
less. As soon as the buds, young fruit, and leaves appear they are promptly 
attacked, the entire crop often being entirely ruined. The leaves are curled and 
weakened, while the young fruit is so distorted as to be killed or rendered unfit 
for market. During the months of April and May winged migratory females 
appear, which start colonies on other trees. The work continues until about the 
middle of July, when most of the lice leave the tops and again go to the roots. 



139. Aphis pomi De Geer 

Figures 225 to 227 

De Geer, Memoires, vol. 3, p. 173, 1773 (orig. desc). 

Davidson, Jour. Econ. Ent., vol. 2, p. 301, 1909 (list). 

Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1911 (list). Aphis mali Fabr. 

Weatherby, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 318, 1912 (list). 

Carnes, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 399, 1912 (list). 

Branigan, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 285, 1915 (list). 

Hurdley, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 445, 1915 (list). 

Baker and Turner, Jour. Agr. Res., vol. 5, pp. 955-995, 1916 (complete 

account). 

Records. — Piiriis mains; Crataegus oxycantha; Catalpa sp. ; California. 

In California this species has been reported on apple and haw- 
thorn {Crataegus sp.) at Stanford University by Davidson and 
Morrison ; in Humboldt County by Weatherby ; at Santa Rosa by 
Carnes ; and by others in Orange, Placer, Sonoma, Santa Cruz, San 
Bernardino, and Monterey counties. Horticultural Commissioner 
Armitage states that it has never been found in San Diego County, 
and Horticultural Commissioner Norton verites that it is unknown in 
Nevada County. These are the only two of the apple growing regions 
of the state in which it is not known. The author has found it at 
Stanford University on apple, catalpa, pear, and hawthorn, and at 
Marysville on catalpa. Gillette lists loquat, quince, and flowering 
crab as additional hosts. It seems to prefer the apple to other hosts, 
and it is on the apple that its greate.st injury is done. Gillette states : 
"Among the apple trees it has its preference. Missouri Pippin seems 
to be its first choice, while Rome Beauty, Black Twig, Ben Davis, and 
a few others are second choice, and the Northern Sp.y is scarcely 
attacked." The fact that the Northern Spy is almost immune is 
interesting in that this variety is also quite immune to the devastations 
of the woolly aphis (Eriosonm lanigfra Hausman). 

The life historj^ of this aphid is quite similar to that of many other 
species, and is as follows: 



A SYNOPSIS OF THE APHIDIDAE 121 

The eggs are laid in the fall of the yeai-, probably during the latter 
part of October, throughout November, and on into December. They 
are laid for the most part on the smooth bark of the suckers and water 
sprouts of the newer shoots. The author has found them in the 
crotches of the twigs and stems where the bark is rougher, but this is 
not the usual place. These eggs hatch in the spring about the time 
the buds begin to show green. In California this is usually during 
March, although some seasons it is as early as the middle of February, 
depending entirely upon the weather conditions. These stem-mothers 
at first feed on the young buds, until the latter have opened enough 
to allow the aphids to crawl down into the curled leaves. Here they 
feed for two or three weeks, when they mature and begin depositing 
living young. This second generation consists chiefly of apterous 
females, whicli mature in from two to four weeks and in turn produce 
young. The following generations are in large part alate females 
which migrate to other trees and there form new colonies. The alates 
are most common at Stanford University during the latter part of 
May and during the month of June. After June they seem to lessen 
in number, perhaps due to the predaceous and parasitic enemies. The 
first alates that the author has found in the spring were taken at 
Stanford University on April 13, 1914. In the fall, often as early as 
October, sexual males and females begin to appear, the males being 
apterous, the females alate. These mate and very soon the female 
lays its eggs. Egg laying begins usually in the latter part of October, 
just as the leaves are beginning to fall, and continues into December 
after the trees are bare. These eggs hatch in the spring into stem 
mothers, and the life cycle is completed. 



140. Aphis prunorum Dobr. 

Figures 228 to 230 

Dobrowljansky, Zur Biol. d. Blattlause d. Abstbaume u. BUrenstaucher, 1913 

(orig. desc). 
Patch, Maine Agr. Exp. Sta., Bull. 233, p. 2(52, 19U (desc. note). 

Records. — Prunus domestica; Walnut Creek (Davidson) ; San Francisco, April, 
1915 (Shinji). 

A species of Aphis, supposed to be this species, has been taken on 
prune and plum in the San Francisco Bay region. It agrees very well 
with Dr. Patch's description listed. However, it may prove to be 
sj^nonymous with Siphocoryne nymphaeae (Linn.). 



122 MISCELLANEOUS STUDIES 



141. Aphis pseudobrassicae Davis 

Figure 231 

Davis, Can. Ent., vol. 46, p. 231, 1914 (orig. desc). 

Records. — Brassica spp. ; Walnut Creek (Davidson), San Diego, Eiverside: 
Saphaiius sp., Riverside, September, 1916, June, 1917: Matthiola annua, Riverside, 
February to May, 1917. 

Oftentimes in the spring this false cabbage aphis is found in large 
colonies on radish, mustard, and so forth. Davidson has taken it in 
the San Francisco Bay region, and the author throughout southern 
California. The first few times that it was observed by the author 
colonies of Aphk brassicae Linn, were also abundant. This led the 
author to doubt its validity, and to undertake some breeding experi- 
ments. In February, 1917, two colonies were started, each from one 
alate female. They were followed through three generations, with the 
result that all tlie individuals proved to be this species. At the same 
time a colony of Aphis brassicae Linn, was started from one alate. 
All tiie progeny of this individual proved to be the same. A. pscudo- 
brassicue Davis differs from A. brassicae Linn, in the following major 
points ; 

A. pseudobrassicae Davis: A. brassicae Linn.: 

Apterae not puh'erulent. Apterae pulverulent. 

Cornicles of apterae longer than hind Cornicles of apterae shorter than 

tarsi. hind tarsi. 

IV of alates with sensoria. IV of alates without sensoria. 

1-42. Aphis ramona Swain 

Figures 232 to 235 

Swain, Trans. Am. Ent. See., vol. 44, p. 14, 1918 (orig. desc). 

Secords. — Eamona stachyoides ; Nordhoff and Santa Paula, Ventura County 
(Swain). 

This species has been taken twice in Ventura County by Essig. 
It was described by the author from the specimens taken by Essig on 
black sage. 

143. Aphis rubiphila Patch 
Patch, Maine Agr. Exp. Sta., Bull. 233, p. 269, 1914 (orig. desc). 
Records. — Subiis spp.; San Jose, May, 1916 (Davidson). 

In the summer of 1916 Davidson found a species of Aphi.s infesting 
loganberries and blackberries in San Jose, which was determined by 
Dr. Patch as A. rubiphila Patch. Essig believes this to be a synonym 



A SYNOPSIS OF THE APHIDIDAE 123 

of A. gossypii Glover, but as the author has not had an opportunity 
to study specimens he believes it best to recognize it as a distinct 
species at present. 

144. Aphis salicicola Thomas 
Figures 188, 238, 237 

Thomas, 111. Lab. Nat. Hist., Bull. 2, p. 8, 1879 (orig. desc). 
Williams, Univ. Neb. Studies, vol. 10, p. 139, 1910 (desc). 
Davidson, Jour. Econ. Ent., vol. 5, p. 408, 1912 (list). 

Records. — Salix laevigata; Berkeley, June, 1915: Salix, sp. ; San Jose (David- 
son). 

This is an uncommon species, found in the San Francisco Bay 
region on willow. The individuals are found in large colonies on 
the terminal shoots and leaves. These colonies consist in large part 
of apterae, there being but a very few alates. The species is quite 
easily recognized by the long cornicles and by the very short second 
branch of the third diseoidal vein. 



145. Aphis sambucifoliae Fitch 

Figure 240 

Fitch, Cat. Homop. N. Y., p. 66, 185 (orig. desc). 
Sanborn, Kan. Univ. Sci. Bull. 3, p. 52, 1904 (desc). 

Eecords. — Sambucus glauca; Oakland, April, 1915 (Essig) ; Berkeley, July, 
1915. 

In 1915 this species was taken twice, once by Essig in Oakland 
and once by the author in Berkeley. This medium-sized black aphid 
occurs in large colonies on the tender shoots and flower heads of the 
common elderberry. In southern California the author has examined 
hundreds of elderberry trees for this form, but has never found it. 
Only once has he found any aphid on elderberry in the south, and 
these proved to be Rhopalosiphum persic-ae (Sulz.). 



146. Aphis senecio Swain 

Figures 2, 4, 6, 241 to 245 

Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909. Aphis sp. (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. A. halceri Cowen (list). 
Davidson, Jour. Econ. Ent., vol. 7, p. 133, 1914. A. hakeri Cowen (list). 
Swain, Trans. Am. Ent. Soc, vol. 44, p. 16, 1918. 

Eecords. — Abutilon sp. ; Stanford University, February, 1915: Ambrosia 
psilostachya ; Berkeley, 1915 (Essig): Amsinckia spp. ; Stanford University, 1909 
(Davidson), 1912 (Morrison); Berkeley, 1915 (Essig): Anthemis spp.; San 



124 MISCELLANEOUS STUDIES 

Francisco Bay region, 1914 (Davidson) ; Pasadena, May, 1917 (Eoy B. Camp- 
bell) : Artemisia spp.; San Francisco Bay region, 1914 (Davidson); Berkeley, 
1915 (Essig): Aster sp.; San Diego, January, 191G; Ontario, January, 1917: 
Baccharis pilularis; Berkeley, 1915 (Essig), Stanford University, 1916 (Ferris): 
Calendula officinale; Berkeley, 1915 (Essig); San Diego, March, 1916; Riverside 
and Orange, February, 1917: Chrysanthemum sp. ; Berkeley, 1914 (Essig); Octo- 
ber, 1915 ; Menlo Park, San Mateo County, March, 1915 ; San Diego, January, 
1916; La Jolla, February, 1916; Ontario, January, 1917: Cytisus proliferus; 
Berkeley, 1915 (Essig): Gnapholium sp. ; Walnut Creek, 1914 (Davidson): Grin- 
dclia cuneifolia; Walnut Creek, 1915 (Davidson) : Selianthus anmius ; San Fran- 
cisco Bay region, 1914 (Davidson): Sumex sp. ; Stanford University, March, 
1915: Salix sp.; Berkeley, 1915 (Essig): Senecio spp.; Stanford University, 1909, 
1910, 1914 (Davidson) ; Santa Paula, 1911 (Essig) ; Palo Alto, February, 1915. 

This is a very common species throughout California, occurring 
on man.y host plants, particularly the Compositae. It is found most 
commonly in the early spring on asters, marigolds, and chrysanthe- 
mums in southern California, and on German ivy and amsinckia in the 
San Francisco Baj' region. For sometime it was believed to be Aphis 
bakeri Cowen, but its variety of host plants so widely different from 
tho.se of bakeri, led to its being identified as a distinct species. It is 
one of the most common in the state, as a glance at the collection 
records will show. 

1-47. Aphis setariae Thomas 

Figures 246, 247 

Thomas, 111. Lab. Nat. Hist., Bull. 2, p. 5, 1878 (orig. desc). 
Williams, Univ. Neb. Studies, vol. 10, p. 141, 1910 (desc). 

Record. — Prunus domestica; San Francisco Bay region (Davidson). 

In some parts of the country this plum louse becomes abundant 
enough to cause serious damage, but it has never been observed to be 
so in California. Davidson writes that he has found it sparinglj' a few 
times in the San Francisco Bay region. The author has never collected 
it, but has had access to specimens from Morrison, taken in Indiana. 



148. Aphis spiraecola Patch 

Patch, Maine Agr. Exp. Sta., Bull. 233, p. 270, 1914 (orig. desc). 

Records. — Spiraea spp.; Stanford University, 1912 (Morrison) ; Walnut Creek, 
Contra Costa County, 1916 (Davidson). 

In the San Francisco Bay region there is a small aphid very 
similar to Aphis pomi De Greer found attacking meadowsweet. David- 
son and Morrison, who have both observed it, believe it to be this 
species. The following brief descriptive notes are from alate females 



A SYNOPSIS OF THE APHIDIDAE 125 

taken b.y Dr. Patch on cultivated spiraea in Orono, Maine. These 
notes are included here as there is no adequate description of this 
species, the only ones^* being very meager notes indeed . 

Alate viviparous females. — Body rather long and narrow, head 
normal with no antennal tubercles. Antennae shorter than body, 
reaching to about tlie base of the fourth abdominal segment. VI spur 
the longest segment, followed by III, which is about two-thirds as 
long. Following III are IV, V, and VI base. The usual primary 
sensoria are present on V and VI, and the accessory sensoria on VI. 
The secondary sensoria are fairly large and circular. There are six 
or seven in an even line along the whole length of III. On IV there 
may be one or two near the middle, or there may be none.- Prominent 
lateral tuliercles are present on the protliorax and on the first and 
seventh abdominal segments. The cornicles are fairly long, slender, 
and taper slightly toward the apex. They are from one and one-half 
to two times as long as the hind tarsi, and subequal to or very slightly 
longer than the cauda. The cauda is fairly long, ensiform, slightly 
constricted before the tip. The wings are normal, witli the second 
branch of the third discoidal nearer the apex of tlie wing tlian the 
base of the first branch. 

Measurements : Body length, 1.19 to 1.33 mm. ; width of thorax, 
0.544 to 0.561 mm.; antennae total. 0.85 to 0.918 mm.; Ill, 0.17 to 
0.1785 mm. ; IV, 0.136 to 0.153 mm. ; V, 0.1275 to 0.1445 mm. ; VI, 
base 0.0935 to 0.102 mm. ; VI, spur 0.238 to 0.255 mm. ; cornicles, 0.1785 
to 0.187 mm. ; cauda, 0.17 mm. ; hind tarsus, 0.102 mm. ; wing length, 
1.97 to 2.04 mm. ; width, 0.748 to 0.782 mm. ; expansion, 4.55 mm. ; 
from base of first branch of third discoidal to wing tip, 0.578 to 0.68 
mm. : from base of second branch to wing top, 0.17 to 0.255 mm. 

149. Aphis tetrapteralis Cockerell 
Cockerell, South. Cal. Acad. Sci., Bull. 1, p. 4, 1902 (orig. deso.). 
Eecord. — Atriplex canescens tctraptera; La Jolla (Cockerell). 

This species has been observed but once, when described by 
Cockerell. He writes: "It differs fi'om Aphis atriplices Linn, by its 
smaller size, mode of life, and shorter cornicles. It seems to be 
related to Aphis monardae Oestlund." In 1916 the author spent 
considerable time hunting for this species in the vicinity of La Jolla, 
but in vain. 



'8 Patch, Eilith M., Maine Aphids of the Eose Family. Maine Agr. Exp. Sta., 
Bull. 23.'!, p. 270, 1914, Aphis spirnecola n.n.; Gillette-, C. P., Plant louse notes. 
Family Aphididae. Jour. Econ. Ent., vol. 3, p. 404, 1910. Aphis spiraeella Sehout. 



126 MISCELLANEOVS STUDIES 



150. Aphis viburnicolens n.sp. 

Eecords. — Viburnum tinus ; Riverside, February to May, 1917; Eedlands, Feb- 
ruary, 1917; Orange, February, 1917: Laurus rotoundifolia, Riverside, March, 
1917. 

Ill the early spring there is a small green and black aphid that 
attacks in great numbers the racemes of laurustinus and laurel in 
Southern California. In fact, it is so abundant at times as to serioiisly 
injure the plants by preventing them from flowering. The leaves 
and buds are verj- stick.y and covered with the sooty mold fungus. 
During April, 1917, all the aphids left the laurel and laurustinus, but 
the alternate host has as yet not been observed. Specimens were sent 
to Gillette and Patch for determination, but neither could identify 
them. Dr. Patch wrote as follows : 

This insect is not spiraecoJa, a slide of which I am sending you. 

spiraecola sp. 

Cornicles longer than III Cornicles shorter than III 

VI spur longer than III VI spur subequal to III 

VI spur longer than IV and V VI spur subequal to IV and V 

IV subequal to V IV longer than V 

I do not know this species. I do not have spiraeella Schout. for comparison. 

Gillette stated concerning tliis species: "This is a species of Aphis 
close to, but almost certainly distinct from, spiracdla Schout., and so 
far as we know, may be new. ' ' 

From this it would appear that the species from laurustinus and 
laurel is a new species, and it is described herewith as such.'" Cotype 
specimens are in the author's private collection, in the collection of 
the University of California in Berkeley, and of the Citrus Experi- 
ment Station in Riverside. 

Alate viviparovs female. — Prevailing color green. Head and 
thorax dusky brown to black. Antennae dusky to black. Beak light 
brown with tip black. Tibiae, femora of fore legs, and basal one-half 
of femora of middle and hind legs brown ; tarsi, tips of tibiae, tips of 
fore femora, and apical one-half of middle and hind femora black. 
Abdomen pale to apple green, sometimes with a few dusky marginal 
spots. Cornicles and cauda black. 



1" The species reported by Davidson (Jour. Econ. Ent., vol. 3, p. 377, 1910) 
as Aphis mali Fabr. from Laurus laurustinus (Fibunmm tinus?) and by Essig 
(Injurious and Beneficial Insects of California, Men. Bull. Cal. Comm. Hort., 
Supp. vol. 4, p. xlvi, 1915) as Aphis pomi De Geer from laurustinus, are probably 
this species. 



A SYNOPSIS OF THE APHIDIDAE 127 

Head normal, with frontal and antenual tubercles absent. An- 
tennae short, reaching only to the second abdominal segment. Ill 
and VI spur subequal ; IV and V subequal and about three-fourths as 
long as III or VI spur. The usual primary sensoria are present on V 
and VI, and the accessory sensoria on VI. Secondary sensoria are 
found on III and IV, from five to nine on the former and from one 
to four on the latter. Cornicles short, subeylindrical, and tapering 
from base toward apex. Cauda fairly long, ensiform, with a slight 
constriction in the middle, the cauda is slightly longer than the hind 
tarsi, and the cornicles a little longer than the caiula. Lateral tuber- 
cles are present on the prothorax, and on the first, fourth, and seventh 
abdominal segments. The cornicles are subequal to IV or V. The 
hind tarsi are somewhat longt'r than VI base. The wings ai"e fairl,y 
large, witli regular venation, the second joint of the third diseoidal 
arising about half way between the tip of the wing and the base of 
the first joint. 

Measurements: Bodj' length, 1.214 to 1.479 mm. (av. 1.372 mm.) ; 
width of thorax, 0.476 to 0.578 mm. (av. 0..5338 mm.) ; antennae total, 
0.733 to 0.918 mm. (av. 0.8925 mm.) ; III, 0.187 to 0.230 mm. (av. 
0.2067 mm.) ; IV, 0.136 to 0.161 mm. (av. 0.1473 mm.) ; V, 0.119 to 
0.153 mm. (av. 0.1416 mm.) ; VI, base 0.085 to 0.102 mm. (av. 0.0877 
mm.) ; VI, spur 0.204 to 0.230 mm. (av. 0.216 mm.) ; cornicles, 0.127 
to 0.153 mm. (av. 0.1422 mm.) ; cauda, 0.110 to 0.136 mm. (av. 0.1252 
mm.) ; hind tarsi, 0.102 to 0.119 nun. (av. 0.1023 mm.) ; wing length, 
1.921 to 2.397 mm. (av. 2.167 mm.) ; width, 0.799 to 0.935 mm. (av. 
0.8704 mm.) ; expansion, 4.42 to 5.304 mm. (av. 4.875 mm.). 

Aptermis viviparous female. — General color green with the follow- 
ing dusky to black : head, antennae, apex of beak, cornicles, cauda, 
distal margin anal plate, tarsi, and tips of tibiae. Legs, except tarsi 
and tips of tibiae, duskj' brownish green. Antennae reach to the ba.se 
of the second abdominal segment. The various segments are propor- 
tionally the same as in the alates. The beak reaches to the distal 
margin of the first coxae or almost to the apical margin of the third 
coxae. Lateral body tubercles are present on thesprothorax and first, 
second, and seventh abdominal segments. Sometkaes they are also 
present on the third, fourth, or fifth abdominal segments as well. The 
cornicles and cauda are subequal, each slightly longq^ than the hind 
tarsi, and of the same form as in the alates. 

Measurements: Body length, 1.326 to 1.462 mm. (av.\1.3685 mm.) ; 
width of thorax, 0.595 to 0.68 mm. (av. 0.6975 mm.) ; antennae total 



128 MISCELLANEOUS STUDIES 

0.731 to 0.782 mm. (av. 0.748 mm.); Ill, 0.153 to 0.187 mm. (av. 
0.170 mm.) ; IV, 0.119 to 0.136 mm. (av. 0.1224 mm.) ; V, 0.119 mm. ; 
VI, base 0.085 mm.; VI, spur 0.136 to 0.1995 mm. (av. 0.1632 mm.) ; 
cornicles, 0.153 to 0.1995 mm. (av. 0.170 mm.) ; caiida, 0.136 to 0.170 
mm. (av. 0.162 mm.) ; hind tarsi, 0.102 to 0.119 mm. (av. 0.114 mm.). 



151. Aphis yuccae Cowen 
Figures 303 to 305 

Cowen, Colo. Agr. Exp. Sta., Bull. 31, p. 122, 1895 (orig. dese.). 
Williams, Univ. Neb. Studies, vol. 10, p. 145, 1910. Aphis yuccicola n.sp. 
(desc). 

Records. — Tmcc-o moliavensis; Moorpark, Ventura County, April, 1916 (F. M. 
Trimble); San Diego, May, 1916. 

Ill April, 1916, Horticultural Inspector F. M. Trimble of Ventura 
County sent the author a few specimens of the alate and apterous 
viviparous females of this species, taken on Spanish dagger in Moor- 
park. In the latter part of tlie next month the author found a few 
apterae on tlie leaves of Spanisli dagger in Golden Hill Park, San 
Diego. There were only a few individuals present at that time, but 
there was evidence of an earlier heavy infestation. Following are a 
few notes to supplement Williams' excellent description of this species. 

Ill is the longest segment of the antennae, followed by VI spur, 
which is about three-fourths as long. IV is next, being a little over 
one-half as long as III and about five-sixths as long as VI spur. V 
is slightly sliorter than IV and is followed closely by VI base, which 
is about one-half the length of the spur. The usual primary sensoria 
are present on V and VI and the accessory sensoria on VI (fig. 303). 
The apterae have no secondary sensoria, while the alates along the 
whole length of III (fig. 304) have about twenty-five irregularl.y 
placed sensoria of irregular size. VI is without sensoria. Lateral 
tubercles are present on the prothorax and on the first and seventh 
abdominal segments. The cornicles (fig. 305) are long and slightly 
tapering, being but slightly shorter than tlie spur of the sixth antennal 
segment and about twice as long as the hind tarsi. The cauda (fig. 
305) is ensiform or sickle-shaped and about three-fourths as long as 
the cornicles. In length it is about equal to the fifth antennal seg- 
ment and one-half again as long as the hind tarsi. 



A SYNOPSIS OF THE APHIDIDAE 129 

Alate viviparous females. — Measurments : Body length, 1.78 to 1.9 
mm. (av. 1.86 mm.) ; width, (thorax), 0.95 mm.; antennae total, 1.38 
to 1.51 mm. (av. 1.449 mm.) ; III, 0.34 to 0.425 mm. (av. 0.391 mm.) ; 
IV, 0.238 to 0.273 mm. (av. 0.256 mm.) ; V, 0.212 to 0.229 mm. (av. 
0.219 mm.) ; VI, 0.136 to 0.17 mm. (av. 0.155 mm.) ; spur, 0.255 to 
0.306 mm. (av. 0.289 mm.) ; cornicles, 0.255 to 0.2975 mm. (av. 0.275 
mm.) ; Cauda, 0.2125 to 0.238 mm. (av. 0.225 mm.) ; hind tarsi, 0.153 
mm.; wing length, 3.06 to 3.4 mm. (av. 3.19 mm.) ; wing width, 1.27 
to 1.46 mm. (av. 1.338 mm.) ; wing expansion, 7.48 mm. 



30. Genus Toxoptera Kooh. 

Koch, Die PflanzenlUuse, p. 253, 1857. Type Aphis aurantii Fonsc. 

152. Toxoptera aurantii (Fonsc) 

Figures 114, 163, 27G 

Boyer de Fonscolombe, Ann. Ent. Soc. France, vol. 10, 1841. Aphis (orig. 

desc). 
Essig, Pom. Jour. Ent., vol. 3, p. 601, 1911. T. aurantiae Koch (desc). 
Davis, XJ. S. Dept. Agr., Bur. Ent., Tech. Ser., Bull. 25, pt. 1, p. 8, 1912. 

Becords. — Citrus spp. ; throughout citrus sections of southern and central Cali- 
fornia (Essig, author) ; San Jose (Davidson). 

This is the common black louse of the citrus trees, and is found at 
almost any time of the year on the younger and more tender leaves 
of various species of Citt-us. It is more or less heavily preyed upon 
by the braconid fly, Lijstphlebus testaccipes Cresson. In fact, the 
author ha-s noticed several infestations in which fully ninety-five per 
cent of the individuals were parasitized. Besides these the sj'rphid 
flies cause great havoc among colonies. Of these the author has reared 
Allograpta obliqua Say from a colony taken in the vieinit.y of El 
Cajon, San Diego County. Never does this species become abundant 
enough to seriously damage trees, due undoubtedly to the effective 
work of its predacious and parasitic enemies. Only in the spring 
are they found to any great extent, although occasionally tliroughout 
the year small infestation can be noticed. 



130 MISCELLANEOUS STUDIES 



31. Genus Hyalopterus Koeli 

Koch, Die Pflanzenlause, p. 17, 1854. Type Aphis arundinis Fabricius (A. 
pruni Fabr.). 

153. Hyalopterus arimdinis (Fabr.) 

Figures 181, 185, 186 

Fabricius, Ent. Syst., vol. 4, p. 212, 1749. Aphis (orig. desc). 

Clarke, Can. Ent, vol. 35, p. 247, 1903 (list). 

Davidson, Jour. Econ. Ent., vol. 2, p. 303, 1909 (list). 

Davidson, Jour. Eeon. Ent., vol. 3, p. 377, 1910 (list). 

Essig, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 569, 1913 (list). 

Essig, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 624, 1913. A. prunifoliae 

Fiteh (list). 
Weldon, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 630, 1913 (list). 
Weldon, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 378, 1914 (list). 
Patch, Maine Agr. Exp. Sta., Bull. 233, 266, 1914 (desc.). 
Davidson, Mon. Bull. Cal. Comm. Hort., vol. 6, p. 64, 1917 (note). 

Bccords. — Prumis spp., Phalaria arundiiuicoa. Phragmitcs comnninis, Typha 
latifolia: central California. 

During the spring and early summer of the year this ' ' mealy-plum 
louse" is often very abundant on various species of Prunus in the 
central part of the state, especially in the San Francisco Bay region 
and the Sacramento Valley. As summer continues all the aphids 
desert the plum for other host plants, where thej' remain until fall. 
The summer hosts in California so far known are reed grass, canarj' 
grass, and tule, or cat-tail rush. In the Santa Clara Valley there is a 
feeling among the prune growers that this aphid is the cause of the 
splitting of the prunes, which is often quite extensive. However, this 
remains to be proven. 

32. Genus Liosomaphis Walker 
Walker, The Zoologist, p. 1119, 1868. Type AphU bcrberidis Kalt. 

154. Liosomaphis berberidis (Kalt.) 

Figures 184, 251, 252 

Kaltenbach, Monog. d. Pflanzenlause, p. 85, 1843. Aphis (orig. desc). 
Davis, Ann. Ent. Soc. Am., vol. 1, p. 254, 1908. Rhopalosiphum (desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 378, 1910. Rhopalosiphum (list). 

Becords. — Berberis vulgaris: Stanford University (Davidson); February to 
May, 1915 ; Berkeley, June to August, 1915. 

This species is found throughout the year on the lower sides of 
the leaves of barberry in the San Francisco Bay region. The apterae 
are often very abundant, but the alates are always quite scarce. This 



A SYNOPSIS OF THE APHIDIDAE 131 

species is similar to species of Rhopalosiphum, particularly in the 
shape of the cornicles and cauda, but owing to the absence of antennal 
tuberek'S it falls into the tribe Aphidini instead of Macrosiphini. 
Hence Walker's genus Liosomaphis is maintained for this species. 



33. Genus Siphocorjoie Passerini 
Passerini, Gli Afidi, 1860. Type Aphis paxtinacae Linn, {xylostei Schrank). 

There has been much diversity of opinion concerning this genus, 
some aphidologists considering it as Siphocoriine Passerini, some as 
Hyadnphis Kirkaldy, and some as a synonym of Rhopalosiphum Koch. 
This last is incorrect as this is most certainly not a Macrosiphini for 
the antennal tubercles are lacking. In 1904 Kirkaldy proposed the 
name Ilijndaphis to replace Siphocoryne, but in the author's opinion 
this is uncalled for, so he maintains the original name, Siphocoryne 
Passerini. 

There have been reported from various parts of California eight 
species of Siphocoryne as follows: caprcae (Pabr. ), conii (Dvdn.), 
foeniculi (Schrank), nymphaeae (Linn.), pastinacae (Linn.), salicis 
(Monell), umhellul-ariae (Dvdn.), and xylostei (Schrank). There 
are, however, really but three species; capreae (Fabr.), nymphaeae 
(Linn.) and pastinacae (Linn.). According to Gillette,^" S. salicis 
Monell is a synonym of S. capreae (Fabr.), and xylostei (Schr.) of 
pastinacae (Linn.). Davidson^^ states that S. conii (Dvdn.) is a 
synonym of xylostei (Schr.), and therefore it is the same as pastinacae 
(Linn.). Morrison writes that the specimens Davidson called S. foeni- 
culi (Sehr.) are capreae (Fabr.), and those he described as Hyadaphis 
umheUulariae n.sp. are jS'. pastinacae (Linn.). These two species, 
pastinacae (Linn.) and capreae (Fabr.), have been greatly confused 
but Gillette-- has worked out their sjoionj-my quite satisfactorilj-. The 
following key for distinguishing them is from his paper. 

Joints 4, 5, 6, and antennal spur subequal, the spur usually distinctly the 
longest, cornicles fully three-fourths as long as third joint of the antenna, a small 
tubercle on the alate form and a large one on the apterous individuals always 
present capreae 



20 Gillette, C. P., Two Shopalosiphum species and Aphis pulverulens n.sp.. 
Jour. Econ. Ent., vol. 4, pp. 320-32.5, 1911. 

21 Davidson, W. M., Plant louse notes from California, Jour. Econ. Ent., vol. 7, 
p. 133, 1914. 

22 Gillette, C. P.. Two Hhopalosiphum species and Aphis pulverulens n.sp., 
Jour. Econ. Ent., vol. 4, pp. 320-325, 1911. 



132 MISCELLANEOUS STUDIES 

Joint 623 of the antenna distinctly shorter than 5, the fourth still shorter 
and its spur nearly as long as joints 4, 5, and 6 combined, cornicles seldom much 
exceeding one-half the third joint of the antenna in length, and a supra-caudal 
tubercle or spine entirely absent pastinacae 

Aphis nymphaeae Linn, has usually been considered by American 
aphidologists as a species of Rhopalosiphuin. but the presence of lat- 
eral body tubercles, the short, robust body, and the absence of antennal 
tubercles place it in the Aphidini rather than the Macrosiphini. 
Therefore, it must be considered as belonging to this genus. Baker-* 
has recently recognized it as belonging here. 

Key to Californian Species 

1. A small spine or tubercle present at the distal end of the body just above the 

cauda (figs. 2-55, 2.56) capreae (Fabr.) 

— No supra-caudal tubercle or spine 2 

2. General color pale green. VI spur as long as IV, V and VI base combined. 

Cornicles at most but slightly more than one-half the length of III. 

pastinacae (Linn.) 

— General color dark brown, wine, or black. VI spur not as long as IV, V and 

VI base combined, although longer than any two together. Cornicles and 
III subequal nymphaeae (Linn.) 



155. Siphocoryne capreae Fabr. 

Fabricius, Ent. Syst., p. 211, 1794. Aphis (orig. desc). 
Clarke, Can. Ent., vol. 3.5. p. 252, 1903. S. foemculi (Pass.) (list). 
Davidson, Jour. Eeon., vol. 2, p. 303, 1909. S. salicis Monell (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. S. focniculi (Pass.), (list). 
Davidson, Jour. Eeon. Ent., vol. 3, p. 377, 1910. S. salicis Monell (list). 
Essig, Pom. Jour. Ent., vol. 3, p. 534, 1911. Eyadaphis pastinacae (Linn.) 
(desc). 

Records. — Foeniculum vulgare; Berkeley and Newcastle (Clarke), Stanford 
University (Davidson): Carum spp. ; Cicuta virosa ; Santa Paula, Berkeley 
(Essig) : Salix laevigata; Santa Paula (Essig), Brea Canyon, Los Angeles County, 
AprO, 1917; Riverside, May, 1917: Salix nigra; Lakeside, San Diego County, 
April, 1916: Salix sp., Stanford University (Davidson). 

This species is found more or less abundantly in the spring on the 
tender shoots and leaves of willows, migrating in early summer to 
various species of Umbelliferae. It is more common than S. pastinacae 
(Linn.), which species is also found on Umbelliferae in the summer, 
but which passes the fall, winter, and spring on lioneysuckle. 



23 In all the author's specimens. VI is shorter than V, which in turn is shorter 
than IV, while VI spur is nearly as long as the three together. 

2* Baker, A. C. and Quaintance. A. L. Aphids injurious to orchard fruits, 
currant, gooseberry and grape, U. S. Dept. Agr., Farmers' Bulletin 804, p. 21, 
1917. 



A SYNOPSIS OF THE APHIDIDAE 133 

156. Siphocorjnie nymphaeae Linn. 

Figure 172 

Linnaeus, Syst. Nat., vol. 2, p. 734, 1735. Aphis (orig. desc,.). 
Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. Bhopalosiplium (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 793, 1912. Ehopalosiphum (desc). 
Davidson, Mon. Bull. Cal. Comm. Hort., vol. 6, p. 65, 1917. Ehopalosiphum 
(note). 

Eecoi-ds. — Polygonum sp., Alisma sp., Potamogetoii sp. ; San Francisco Bay 
region (Davidson) : Typha latifolia; Santa Paula (Essig), San Francisco Bay 
region (Davidson): Nymphaea sp.; San Francisco Bay region (Davidson), 
Fresno, June, 1915: Prunus domestica ; Berkeley, 1916 (Essig). 

This aphid occurs tlirougliout the summer montlis on various semi- 
aquatic plants, lily, tule, and so forth. In the fall it migrates to 
plum, where eggs are laid. The first two or three generations in the 
spring occur ou plum, but about June there is a migration to its sum- 
mer host plants. So far it has been found in southern California 
only in Ventura County. 

The species listed as Aphis prunorum Dobr. (see no. 140) may be 
this species. Essig believes it is, but the author is not certain so does 
not list it as a synonym. 



157. SiphocorjTie pastinacae Linn. 
Figures 266 to 270 

Linnaeus, Syst. Nat., p. 451, 1735. Aphis (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909. S. xylostei (Schr.) (list). 
Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909. S. conii n.sp. (desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. S. xylostei (Sehr.) and 

S. conii Dvdn. (list). 
Davidson, Jour. Econ. Ent., vol. 4, p. 599, 1911. Hyadaphis umbellulariae 

n.sp. (desc). 
David.son, Pom. Jour. Ent., vol. 3, p. 399, 1911. S. conii Dvdu. (list). 
Davidson, Jour. Econ. Ent., vol. 7, p. 133, 1914. S. xylostei (Schr.) (list). 

Eecords. — Lonicera sp.; Stanford University (Davidson), Claremont (Essig), 
Berkeley, AprU, 1915: Umbellularia calif orni-ca; San Jose (Davidson): Conium 
macalatum ; Stanford University, Penryn, Placer County, and San Jose (David- 
son). 

This aphid occurs on honeysuckle during the winter and spring, 
and on various semiaquatic plants in the summer. It has been taken 
in southern California, in the San Francisco Baj" region, and in the 
Sacramento Valley. 



134 MISCELLANEOUS STUDIES 



34. Genus Myzaphis Van der Goot 

Van der Goot, Ziir Sjstematik der Aphiden, Tijdserift voor Entomologie, 
vol. 56, p. 96, 1913. Type Aphis rosarum Walker. 

The author believes that this genus of Van der Goot's should be 
accepted for the two following species: Aphis abietiim Walker and 
Aphis rosarum Walker. A. rosarum has usually been considered as 
belonging to the genus Myzus, but the absence of antennal tubercles 
excludes it from that genus (see figs. 306-308, 313). The cornicles 
and cauda are not typical of Aphis, and these together with the dis- 
tinctive frontal tubercle on the head and the absence of lateral bod.y 
tubercles distinguish it from Aphis. Consequently this genus should 
be recognized. Following is a key for separating the two known 
species, both of which occur in California: 

Cornicles slightly clavate (figs. 312, 315), shorter than III. Ill tuberculate, IV 

without sensoria (fig. 309). Found on Hosa spp rosarum (Walker) 

Cornicles cylindrical (fig. 197), equ.il to or longer than III. Ill with 9 to 12 
rather large secondary sensoria, IV with 1 to 4 (fig. 196). On conifers. 

abietina (Walker) 

• 158. Myzaphis abietina (Walker) 

Figures 196, 197 
Walker, Ann. Mag. Nat. Hist., vol. 3, p. 301, 1848. Aphis (orig. desc). 
Wilson, Proc. Ent. Soc. Brit. Columbia, June, 1915 (desc). 
Record. — Picea excelsa; San Francisco, March, 1915 (Compere). 

The only report of this species in America is that of Wilson, who 
found it on spruce {Pirca sp.) at Vancouver, British Columbia. On 
March 26, 1915, Harold Compere of San Francisco took a number of 
specimens of this species on the twigs of Norway spruce {Picea 
excelsa) in Golden Gate Park, San Francisco. The specimens are in 
Essig's and tlie author's collections. 

159. Myzaphis rosarum (Walker) 
Figures 308 to 317 
Walker, Ann. Mag. Nat. Hist, vol. 3, 1848. Aphis (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 379, 1910. Myzus (list) 
Becords. — Rosa spp.; Stanford University (Davidson); Santa Paula (Essig), 
San Diego, March to July, 1916. 

This species has been reported in the San Francisco Bay region 
by Davidson and in Santa Paula by Essig. In the Bay region it is 
rather scarce and is second to Macrosiphum rosae (Linn.) in abun- 
dance on roses. The author has taken it at Stanford University in 
1915, and in San Diego several times in 1916. In San Diego in 1916 
it was by far the most abundant rose-infesting aphid. The author 



A SYNOPSIS OF THE APHIDIDAE 135 

has observed it iu such numbers on roses as to cover the undersides 
of practically all the leaves and the calyx cups of the flowers. Iu some 
cases the buds were stunted and the flowers unshapely from its effect. 
In the rose garden of the Panama-California International Exposition 
these aphids were of considerable importance, necessitating continual 
care to keep them under control. 

Since there is no adequate description of this species in the Ameri- 
can aphid literatm-e the author describes it herewith. The following 
description was drawn from ten specimens of alate and eight of 
apterae, collected in Santa Paula, Stanford University, and San Diego. 

Alate viviparous female. — Color notes (taken from notes made 
at the time of collection of specimens at Stanford in March, 1915) : 
Head, antennae, and thoracic plates black. Abdomen pale apple green 
with smoky blotch on dorsum. Legs : apical two-thirds of femora 
smoky, basal one-third pale, tibiae pale except dusky tip, tarsi dusky. 
Cornicles green (dusky), cauda pale apple green. 

Head is twice as wide as long with a fairly distinct tubercle on the 
front (fig. 308). Antennal tubercles are lacking or very indistinct. 
Antennae reach almost to the base of the third abdominal segment 
(figs. 309, 310). Ill is the longest segment, followed by IV, spur, V, 
and VI. The spur and IV are practically equal. Of sixteen antennae 
examined, in three, the spur and IV were equal, in ten, IV was slightly 
longer than the spur, while in three, the spur was slightly longer than 

IV. V is slightly shorter than the spur, and VI slightly shorter than 

V. However, IV, spur, V, and VI are all almost equal. On V and VI 
are the usual primary sensoria, and VI the accessory sensoria (fig. 
300). Ill is tuberculate, being furnished with a large number of 
irregularly placed secondary sensoria (fig. 309). IV is without any 
sensoria. The beak reaches almost to the second coxae. 

The prothorax is without lateral tubercles. The wings are normal, 
being about twice the length of the body. The second branch of the 
cubitus arises nearer the apex of the wing than the base of the first 
branch (fig. 311). In but one of seventeen specimens examined was 
the origin of the second branch of the cubitus nearer the base of the 
first branch than the tip of the wing. In this specimen the measure- 
ments were : 0.561 mm. from tip of wing to base of first branch and 
0.289 mm. from tip of wing to base of second branch. 

The abdomen is long and narrow and is without lateral body 
tubercles. The cornicles (fig. 312) are long, being but slightly shorter 
than the third antennal segment, and over twice as long as the hind 
tarsi. They are slightly clavate on the inner side. The cauda (fig. 



136 MISCELLANEOUS STUDIES 

312) is long and pointed (ensiform), being slightly more than one-half 
as long as the cornicles and about one-half as long again as the hind 
tarsi. 

Measurements: Body length, 1.19 to 1.41 mm. (av. 1.28 mm.); 
width of thorax, 0.459 to 0.527 mm. (av. 0.487 mm.) ; antennae total, 
0.85 to 1.156 mm. (av. 1.027 mm.) ; III, 0.255 to 0.34 mm. (av. 0.317 
mm.) ; IV, 0.1275 to 0.2295 mm. (av. 0.1768 mm.) ; V, 0.119 to 0.17 
mm. (av. 0.1365 mm.); VI, 0.085 to 0.119 mm. (av. 0.1095 mm.); 
spur, 0.119 to 0.204 mm. (av. 0.1695 mm.) ; cornicles, 0.238 to 0.306 
mm. (av. 0.2574 mm.) ; cauda, 0.136 to 0.187 mm. (av. 0.1588 mm.) ; 
hind tarsi, 0.119 to 0.136 mm. (av. 0.1205 mm.) ; wing length, 2.482 
to 2.72 mm. (av. 2.5483 mm.) ; wing width, 0.884 to 1.02 mm. (av. 
0.9396 mm.) ; wing expansion 5.423 to 5.967 mm. (av. 5.5836 mm.). 
From tip of wing to base of first branch of cubitus 0.561 to 1.037 mm. 
(av. 0.8041 mm.) ; from tip of wing to base of second branch of cubitus, 
0.17 to 0.34 mm. (av. 0.2907 mm.). 

Apterous viviparous female. — Head about as long as broad with a 
large prominent tubercle on the front, this tubercle being considerably 
larger than in the alate form ; in some individuals it is fully as large 
as the first antennal .segment (fig. 313). Antennal tubercles small but 
distinct, similar to those of the alate. Antennae (fig. 314) short, 
reaching only to the third coxae. Ill is the longest segment, followed 
by the spur, IV, VI, and V. These are all subequal, the fornuila of 
the averages being spur, IV, VI, and V. The formulae for seven 
antennae are S, VI (V, IV) ; S, (VI, V, IV) ; S, V, IV, VI; S, IV (V, 
VI) ; S, (IV, V), VI; IV (V, VI, S) ; (S, VI, IV), V. The usual 
primary sensoria are present, but there are no secondary sensoria. 
The beak is short, reaching only to the second coxae. 

The prothorax is without tubercles. The thorax is normal, as are 
the legs. The abdomen is long and narrow, without lateral tubercles, 
and without long capitate hairs as found in some species of Myziis. 
The cornicles (fig. 315) are long, cylindrical, and slightly tapering 
toward the apex, or slightly clavate at apex. They are over twice as 
long as the third antennal segment and over three times as long as 
the hind tarsi (fig. 317), and half as long again as the cauda. The 
Cauda (fig. 316) is long and ensiform, being slightly more than twice 
the length of the hind tarsi, and about two-thirds the length of the 
cornicles. 

Measurements: Body length, 1.275 to 1.615 mm. (av. 1.428 mm.) ; 
width of thorax, 0.493 to 0.748 mm. (av. 0.6375 mm.) ; antennae total, 
0.544 to 0.731 mm. (av. 0.6239 mm.) ; III, 0.153 to 0.238 mm. (av. 



A SYNOPSIS OF THE APHIDIDAE ■ 137 

0.178 mm.) ; IV, 0.068 to 0.119 mm. (av. 0.0855 mm.) ; V, 0.068 to 
0.102 mm. (av. 0.0833 mm.) ; VI, 0.068 to 0.119 mm. (av. 0.085 mm.) ; 
spur, 0.085 to 0.136 mm. (av. 0.117 mm.) ; cornicles, 0.306 to 0.442 
mm. (av. 0.3655 mm.) ; eauda, 0.204 to 0.272 mm. (av. 0.2338 mm.) ; 
hind tarsi, 0.102 mm. (Note : no color notes were taken of the apterae 
at the time of collection and as all the specimens were killed in alcohol, 
dehydrated in xylene and mounted in Canadian balsam, it is impossible 
to give any color notes.) 

35. Genus Coloradoa Wilson 

Wilson, Ann. Ent. Soc. Am., vol. 3, p. 323, 1910. Type Aphis rufoniaculaia 
Wilson. 

This genus was described by Wilson in 1910 to contain the species 
Aphis rufo-rnaculata Wilson. After examining specimens of this 
species recently, the author is of the opinion that Coloradoa and 
Myzaphis are synonymous, for there does not seem to be enovigh differ- 
ence between this species and the two species of Mijzaphis to warrant 
a separation of genera. However, the author does not feel certain 
concerning the point, so lists both these genera. Should they later 
prove to be synonymous, Myzaphis would have to be dropped and 
replaced by Colorarloa. There is but one species belonging to this 
genus. 

160. Coloradoa rufomaculata Wilson 

Wilson, Ent. News, vol. 14, p. 261, 1908. Arihis (orig. desc). 
Secord. — Chrysanthemum, cultivated; Sacramento, April, 1917 (Davidson). 

The author has recently received specimens of this species from 
Davidson taken on chrysanthemum in Sacramento. 

36. Geuus Cerosipha Del Guercio 

Del Guercio, Nouve relazione agraria di Pirenze, vol. 2, p. IIB, 1909. Type 
C. passeriniana n.sp. 

]61. Cerosipha cupressi Swain 
Swain, Trans. Am. Ent. Soc, vol. 44, p. 19, 1918 (orig. desc). 
Becords. — Cupressus guadelupensis ; San Diego, 1916; Eiverside, 1917; C. 
macrocarpa, San Diego, 1916. 

This species, recently described by the author, has been taken by 
him several times in San Diego and Riverside on blue cypress and 
Monterey cypress. It is an extremely interesting little aphid, differ- 
ing considerably from any other species known to the author, both 
in habits and appearance. Its five-jointed antennae, long cauda, 
atrophied cornicles, and convexitj'- of abdomen are quite distinctive. 



138 • MISCELLANEOUS STUDIES 



Subfamily Pemphiginae Mordwilko" 

Mordwilko, Ann; Mus. Zool. Imp. Acad. Sci. St. Petersburg, vol. 13, pp. 
362-364, 1908. 

A summary of Mordwilko "s description of tliis subfamily has 
already been given. The latest and probably the most complete sj'S- 
tematic work on this subfamilj' that has been done is that of Dr. Albert 
Tullgren of Stockholm, Sweden, in liis paper, " Aphidologische 
Studien I" in 1909. Tullgren divides this subfamily into six tribes, 
viz: Vacunina, Hormaphidina, Mindarina, Pemphigina, Sehizoneu- 
rina, and Anoeciina. In the tribe Vacunina he places Vacunu Heyden 
and Glyphina Koch ; in Hormaphidina is the one genus Hmnwmelistes 
Shimmer; in Mindarina is the one genus Mindarus Koch; in Pem- 
phigina he places Asiphum Koch, Pachijpappa Koch, Prociphilus 
Koch, Thecabhis Koch, and Pemphigus Hartig; in Schizoneurina he 
places the two genera, Schizoneura Hartig, and Tetraneura Hartig; 
and finalh' in the Anoeciina is found the one genus Anoccia Koch. It 
can be seen that he uses several of Koch 's genera which have not here- 
tofore been generally used, namely: Prociphilus Koch, Thecabius 
Koch, Asiphum Koch, and so forth. Lately there has been a tendency 
among American aphidologists to accept these genera, and thus to 
divide up the larger genus Pemphigus into these smaller ones. Mord- 
wilko in his keys divides this subfamily into four groups, namely: 
Hormaphidina, Pemphigina, Schizoneurina, and Vacunina. In Hor- 
maphidina he includes besides the genus Hamamilcstcs Shimmer, the 
genera Ilurmuphis Osten-Sacken and C< rata phis Lichtenstein. In 
Pemphigina he includes Pentaphis Heyden, Tetraneura Hartig, 
Pemphigus Hartig, Aplone.ura Passerini, Rhizoctonus Horvath, and 
Paraclrtus Heyden. In Schizaneurina he places Lowia Lichtenstein, 
Colopha Monell, Paehi/pappa Koch, Sehizeineura Hartig, Anoecia Koch, 
and Mindarus Koch. In Vacunina he includes but the one genus 
Vacvna Heyden, which he does not separate from Glyphina Koch. 

There is considerable difference in the classifications of these two 
authors, bat as far as we are concerned here in California our genera 
are placed about the same by both. Following is a translation of 
Mordwilko 's key to the groups: 



25 The author has innlcr way a more exhaustive study of tliis subfamily, par- 
ticularly of the species of Pcniphiflus and Frocipliilus. As this research is still 
in progress, however, it was tliouglit best to omit any report of it, the author here 
confining himself merely to the records of the presence of the various species in 
California. It was hoped to have this study completed at the present time, but 
the unprecedented conditions of this season have made it necessary to delay further 
study for the time being. 



A SYNOPSIS OF THE AFHIDIDAE 139 

1. Winged forms with a cucurbit-shaped cauda. Nymphs that failed to molt 

with three-joiutcd antennae. Winged forms with three to five-jointed 
antennae, which are coarsely ringed from the third on. Wingless partheno- 
genetic females presenting the appearance of the larvae of other families, 
as of some kinds of Coccidae, or of species of Aleyrodes. Sexual forms 
with beaks Group Hormaphidina 

— Winged forms without distinct cauda. Nymphs that failed to molt with four 

to five-jointed antennae. Antennae of winged females five-to six-jointed. 
Sensoria may be found on the third and following joints, often in the 
form of arches or half rings, but never as complete rings 2 

2. Cubitus [third discoidal vein] of the fore wings simple. Cornicles, which are 

pore or pointlike, present only in some species, and then not in all forms. 

Group Pemphigina 

— Cubitus [third discoidal vein] of fore wings once-branched. Cornicles mostly 

point or pore-like 3 

3. Antennae of winged forms six-jointed. Wings held roof-like when at rest. 

Group Schizoneurina 

— Antennae of winged forms five-jointed. Wings held flat when at rest. 

Group Vacunina 



Grou}) Hormaphidina Mordw. 

Mordwilko, Ann. Mus. Zool. Imp. Acad. Sci. St. Petersburg, vol. 13, pp. 
364-365, 1908. 

The antennae of the winged forms are 5- to 3-joiuted (?). With the exception 
of the first two joints they are closely and entirely ringed. Even in the genus 
Morvwphis O.-S., where the antennae are 3-jointed, they may probably be con- 
sidered morphologically as of five joints. The wings are held flat at rest. There 
are four transverse veins on the fore wings, the third of which [third discoidal] 
is simple. The first two [first and second discoidals] originate at the same point 
on the subcosta. The hind wings have one or two transverse veins, in the latter 
case both originating at the same point. The wingless parthenogenetie females 
on the alternate host plants (for example on birch) are mostly circular in shape, 
and have small wax tubes around them. Other forms are coccid-like. The sexual 
forms have beaks. The cornicles are absent. 

This is a description as gjiven by Mordwilko in tiie above mentioned 
paper. Below is a key to the genera, as given by Mordwilko and by 
Van der Goot, tlir latti r of whom inelndes in this group tlie two 
genera IIama>nelestes Shimmer and Cerataphis Licht. 

1. Antennae of winged females plainly five-jointed 2 

— Antennae of winged females only three-jointed Hormaphis O.-S. 

2. Antennae always five-jointed. Front of head always with two little horns. 

Third discoidal once-branched Cerataphis Lichtenstein 

— Antennae of apterous forms three- or four-jointed. Front without horns. 

Third discoidal simple HamameUstes Shim. 



140 MISCELLANEOUS STUDIES 



37. Genus Cerataphis Liehtenstein 

Lichtensteiu, Bull. Societe eiit. de France, vol. 2, p. 16, 1882. Type Coccus 
lataniae Boisd. 

162. Cerataphis lataniae Boisduval 

Boisduval, Ent. Hort., 1867. Coccus (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 5, p. 404, 1912 (list). 
Essig, Univ. Calif. Publ. Entom., vol. 1, p. 342, 1917 (list). 
Secords. — Fern, Stanford University (Davidson); orchid, Oakland (Essig). 
This coecid-like species has been reported twice in the San Fran- 
cisco Bay region, by Davidson and by Essig. Morrison and the author 
have also taken it on the same ferns on which Davidson found it in 
the Stanford University nursery. 



Group Pemphigina Liehtenstein 

Below is a key to the California genera of this group, adapted 
from Mordwiiko, Tullgren and Del Guercio. Del Gucrcio described 
a genus in 1909 for Pemphigus radicicola Essig, which he called 
Trifidaphis. 

1. Antennae of alate females five-jointed Trifidaphis Del Guar 

— Antennae of alate females si.\-jointed 2 

2. Stem mothers with five-jointed antennae. Wax-gland plates on head always 

present and usually large. Spring and fall migrants with wax-gland plates 
always on mesothorax and abdomen, and usually on head. Dorsal pores 
never present 3 

— Stem mothers with four- jointed antennae. Head normally without wax-gland 

plates. Dorsal pores sometimes present. Stem mothers and spring migrants 
(fundatrix and fundatrigenia) at first live in the same closed galls. 

Pemphigus Hartig 

3. Secondary sonsoria furnished with hairy fringe (Wimperkranz). Wax-gland 

plates generally large. In stem mothers there appear four very large pro- 
notal wax-gland plates, placed in a transverse row. All plates have a 
clearly chitinized border. Stem mother and migrants live together. 

Prociphilus Koch 

— Secondary sensoria without hairy fringe (Wimperkranz). Wax-gland plates 

generally small. In stem mothers there are six pronotal plates, of which 
the four middle ones are arranged in the form of a trapezium. In the 
winged fall migrants (sexupara) there are also transverse abdominal gland 
plates, which are without clearly chitinized borders. Stem mothers and 
spring migrants live in separate galls Thecablus Koch 



A SYNOPSIS OF THE APHIDIDAE 141 



38. Genus Trifidaphis Del Guercio 

Del Guercio, Kiv. di patal. veg., vol. 3, p. 20, 1909. Type Pemphigus radi- 
cicola Essig. 

163. Trifidaphis radicicola Essig 

Essig, Pom. Jour. Ent., vol. 1, p. 8, 1909. Pemphigus (orig. deac). 
Baker, Pom. Jour. Ent., vol. 1, p. 74, 1909. (Translation of Del Guer- 
cio 's description of the genus.) 
Essig, Pom. Jour. Ent., vol. 2, p. 283, 1910 (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912 (list). 

Becords. — Amarantlius retroftexus, Solanum douglasii; Claremont, Santa Paula 
(Essig). 

Essig described this species from specimens taken on the roots of 
Amaranthvs rctroflcxus and Solanum douglasii in Santa Paula and 
Claremont. Later Del Guercio described a new genus for this species 
based on the venation and the antennae. It seems that the type speci- 
men of this species had but five-jointed antennae and so of course 
it could not belong to the genus Pemphigus. On an examination of 
eight specimens, including the type specimen and seven eotj^pes, the 
autlior finds that the number of joints in the antennae are variable. 
The type specimens had both antennae with but five joints. Six 
antennae had but five joints, six had six distinct joints, and four had 
five joints in which the division into six could be made out. This 
divison was in the third joint at about one-third the distance from the 
apex. Consequently one could say that this species was tj'pically five- 
jointed, but with some specimens with the third joint divided into two, 
or it could be said that it was typically six-jointed, but in some speci- 
mens a reducton occurred through the joining of the third and fourth 
segments. As but a few specimens were examined the author is not 
willing to state which is the more common, hence leaves this as a valid 
genus, although he is of the opinion that this really belongs to the 
genus Prociphilus Koch. 

39. Genus Pemphigus Hartig 

Hartig, Jahresb. u. d. Eortsohr. d. Forstwiss. u. forstliche Naturk., vol. 1, 
p. 645, 1837. Type Aphis iursarius Linn. 

This genus is represented in California by three well known 
species,-" P. betae Doane, P. populi-caulis Fitch, and P. popuU-tram- 



2s There has been taken several times a species forming elongate leaf galls on 
Populus fremontii, both in the San Francisco Bay region by Davidson and in San 
Diego County by the author, that structurally seems to be identical with P. populi- 
caulis Fitch, but its gall is quite distinct, being more or less similar to that of 
P. betae Doane. Further study may reveal the identity of this form. 



142 MISCELLANEOUS STUDIES 

i-erstts Eiley. All of these species, during' at least a part of their life 
cycles, infest various species of Populus, where thej- form more or less 
distinctive galls. 

Key to Fundatrigeniae^j 

1. Secondary sensoria present only on III. Galls formed on leaf petioles, with a 

transverse opening on the outside of the curve populi-transversus Riley 

— Secondary sensoria on other segments as well as on III 2 

2. Secondary sensoria on III to VI inclusive. Galls formed by the tAvisting of 

the petiole with an oblique opening on the inside of the curve. 

populi-cauUs Fitch 

— Secondary sensoria on 111 and IV.23 Gall formed on tlie under side of the 

leaves, being more or less elongate and opening on the upper side. 

betae Doane 

164. Pemphigus betae Doane 

Doane, Ent. News., vol. 11, p. 390, 1900 (orig. desc). 

Clarke, Can. Ent., vol. 35, p. 248, 1903 (list). 

Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909 (list). 

Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910 (list). 

Williams, Univ. Neb. Studies, vol. 10, p. 92, 1910. P. halsamifcrae n.sp. 

(desc. fundatrigenia). 
Essig, Pom. Jour. Ent., vol. 4, p. 299, 1912 (list). 
Maxson, Jour. Econ. Eut., vol. 9, p. 500, 1916 (note). 

Records. — Beta vulgaris: San Francisco Bay region, Monterey County, Sacra- 
mento Valley. {Eumex spp., Chcnopodiuin spp., etc.?) 

Under the name P. bctac Doane, Clarke, Davidson, and Essig have 
reported a species of aphid infesting the roots of sugar beets, dock, 
Chenopodium, and other plants throughout California. 

Originally this species was described from " specimens taken on 
sugar beet in "Washington, but later-" it was proven that a species 
forming elongated leaf galls on Poindus halsmiiifera in the spring 
migrated to beets, and was identical with this species. In 1916 Maxson 
(cited above) states that his investigations point to the fact that in 
Colorado there are more than one species of Pemphigus attacking the 
sugar beet, one of which is this species that forms the elongate leaf 
gall on poplar in tlie spring, and which is known now as P. hetae 
Doane. 



~^ At present only a key to the alate migrants or fundatrigeniae occurring in 
galls on poplar is given. It is hoped that later, keys to all forms may be formu- 
lated. At present, however, the life histories of the species are not sufficiently 
known. 

28 The sexupara or ^late migrants from beets to popUars have secondary sen- 
soria on III to V inclusive. These form no galls on poplar, however. 

2» Parker, The life history of the sugar-beet root louse, Jour. Econ. Ent., vol. 
7, pp. 13fi-141, 1914; 

GUlette, Notes on some Colorado aphids having alternate host plants, Jour. 
Econ. Ent., vol. 8, p. 97, 1915. 



A SYNOPSIS OF THE APHIDIDAE 14.1 

These observations of Maxson's together with those made by the 
author lead to the conclusion that all the reported cases of infestation 
of beets and other hosts by P. hetae Doane in California do not neces- 
sarily refer to this species. Never have the fundatrix or fundatrigenia 
been taken on poplar in California. This strengthens the point that 
the aphids on beets and other hosts may not all be P. hetae Doane. 
Further studies and observations will have to be made before this 
point can be settled, however. 

165. Pemphigus populicaulis Fitch 

Fiteh, Rep. Ins. N. Y., vol. 5, p. 845, 1859 (orig. desc). 

Clarke, Can. Ent., vol. 35, p. 248, 1903 (list). 

Davidson, Jour Eeon. Ent., vol. 2, p. 299, 1909 (list). 

Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910 (list). 

Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. P. popuU-transversus Riley 

(list). 
Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. P. popuU-transversus Riley 

(list). 
Essig, Pom. Jour. Eut., vol. 4, p. (i99, 1912 (list). 
Essig, Pom. Jour. Ent, vol. 4, p. 708, 1912 (desc). 
Davidson, Jour. Eeon. Ent., vol. 8, p. 420, 1915 (se.xuales). 

Records. — Populus fremontii, P. trichocarpa ; from Placer County to San Diego 
County (Clarke, Davidson, Essig. Morrison, and the author). 

The species infests cottonwoods througliout the state, forming a 
gall by the twisting of the leaf petiole. The sexuales are found, 
according to Davidson, under the bark where the eggs are also laid. 
The author has found the species in San Diego County, having taken 
the fundatrix, virgogenia, and fundatrigenia in galls in May, 1916, 
and the dead sexupara at the same time in old galls. These latter 
probably- died without ever leaving the galls. 



166. Pemphigus populi-transversus Riley 

Riley, U. S. Geog. Geol. Surv., Bull. 5, p. 15, 1880 (orig. desc). 
Essig, Univ. Calif. Publ. Entom., vol. 1, p. 343, 1917 (list). 

Eecords. — Populus fremontii, Berkeley, September, 1914 (Essig), Riverside 
September to October, 1916, May to July, 1917. 

This species forms large galls on the leaf petioles of poplar some- 
what similar to the preceding species, differing in that the opening is 
on the opposite side of the gall, and is transverse rather than oblique. 
Essig "s specimens were determined b}^ Gillette, the author's by Max- 
son. Davidson reported a species under this name from Stanford 



144 MISCELLANEOUS STUDIES 

University, but later wrote the author that he was mistaken in his 
determination, the species being P. populicaulis Fitch instead. 

Just recentl.y the author received specimens of the sexupara of this 
species from J. R. Parker, Bozeman, Montana. These were taken by 
S. H. Jones in Port Allen, Louisiana, in September, 1915, on the roots 
of cabbages. Jones notes that cabbage and other cruciferous plants 
are the alternate ho.st of this species. This spring the author received 
a large number of apterae of a species of Pemphigus taken in Orange 
County on the roots of cabbage. A specific determination of the 
species was impossible but it may have been this one. 

40. Genus Thecabius Koch 
Koch, Die Pflanzenlause, p. 294, 1857. Type Pemphigus affini^ Kalt. 

This genus is very similar to Prociphihis, and by some authors, 
particularly Baker, ^^ is considered as synonymous. However, for 
present purposes tlie author proposes to retain it for the three species 
included herewith. 

Key to CALiroBNiAN Species 

1. Antennae short, barely reaching to the metathorax, and not ouc-third as long 

as the body. Ill but slightly longer than VI popuU-monilis Riley 

— ■ Antennae longer, reaching beyond the base of the abdomen, and about one-half 
as long as the body. Ill considerably longer than VI 2 

2. V and VI with secondary seusoria populi-condupllfoUus Cowen 

■ — ■ VI without secondary sensoria califomicus Davidson 



167. Thecabius califomicus (Davidson) 

Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. Pemphigus ranunculi n.sp. 

(orig. desc). 
Davidson, Jour. Econ. Ent., vol. 4, p. 414, 1911, renamed Pempliigus cali- 

fornicus Dvdn. 
Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912. Pemphigus (desc. ala. and 

apt. female). 
Davidson, Jour. Econ. Ent., vol. 7, p. 127, 1914 (note). 

RecordJi. — Uanunculus califomicus ; San Francisco Bay region (Davidson, Mor- 
rison, Essig, author) : ? Populus sp. ; Walnut Creek, Contra Costa County, May, 
1915 (Davidson) : Fraxinus oregona; Walnut Creek (Davidson). 

This aphid is found quite abundantly on the roots and stems of 
the small California buttercup in the San Francisco Bay region. 
According to Davidson there is a migration during April from butter- 



' Baker, A. C, Identity of Eriosome pyri, Jour. Agr. Ees., vol. 5, p. 1118, 1916. 



A SYNOPSIS OF THE APHIDIDAE 14.1 

cup to ash. There may be a migration to poplar as well, for the 
author has specimens that seem to be this species taken by Davidson 
on poplar. Gillette" places this species as a synonym of T. populi- 
conduplifoUus Cowen, which attacks both Ranunculus and Populus 
in Colorado. Davidson, however, is convinced that they are distinct. 



168. Thecabius populiconduplifolius (Cowen) 

Cowen, Colo. Agr. Exp. Sta., Bull. 31, p. 11.5, 1895. Pemphigus (orig. 

desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Pemphigus (li.st). 
Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912. Pemphigus (list). 
Gillette, Annals Ent. Soc. Am., vol. 7, p. 61, 1914 (desc. and life history). 

Becord. — Populus trichocarpa; Stanford University (Davidson). 

This species was reported b}^ Davidson on poplar at Stanford 
University. Since then no further records of its occurrence in the 
state have been made. In Colorado, Gillette finds that the common 
buttercup, Ramincuhis sp., is an alternate host and so considers the 
preceding species as a synonj'm. This may be possible, but it is quite 
doubtful. 



169. Thecabius populimonilis (Riley) 

Eiley, U. S. Geol. Surv., Bull. 5, p. 13, 1879. Pemphigus (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Pemphigus (list) 
Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. Pemphigus (list). 
Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912. Pemphigus (list). 
Gillette, Ann. Ent. Soc. Am., vol. 6, p. 48.5, 1913 (desc. and life history). 

Becords. — Populus spp. ; Tulare and Placer counties (Davidson); Santa Paula 
(Essig), Riverside, 1916-1917. 

Throughout central and southern California this species is found 
on various species of Populus where it forms more or less globular 
galls on the upper side of the leaves near the margins. In the vicinity 
of Riverside the j'oung stem mothers began to appear in April (1917). 
When first observed in September, 1916, nearly all the galls were 
empty while a few contained alate migrants (sexupara probably). 
According to Gillette the eggs are laid on the ti'unks of Populus, thus 
the entire life cycle is passed on the one host plant. This is rather 
unusual for the Pemphiginae of this section. 



31 Gillette, C. P., Some Pemphiginae attacking species of Populus in Colorado, 
Ann. Ent. Soc. Am., vol. 7, pp. 61-65, 1914. 



146 MISCELLANEOUS STUDIES 

41. Genus Prociphilus Koch 
Koch, Die Pflanzenlause, p. 279, 1837. Type Aphis bumeliae Schrank. 
Key to Califoenian Species 

1. Stigma of forewings conspicuously darkened. V witli a few annular secondary 
sensoria, VI with or without any. Dorsal thoracic wax plates small and 

oval alnifoliae (Williams) 

— Stigma not oonspicuously darkened. V and VI without annular secondary 
sensoria. Dorsal thoracic wax plates quite large and triangular. 

venafuscus Patch 

170. Prociphilus alnifoliae (Williams) 

Williams, Univ. Neb. Studies, vol. 10, p. 91, 1910. Pemphigus (orig. desc). 
Baker, Jour. Agr. Ees., vol. 5, p. 1118, 1916 (note). 

Becords. — Heterorncles arbutifoliae; Sespe, Ventura County, March, 1915 (S. 
H. Essig); May, 191.5 (C. P. Clausen). 

There has been no record of this species from California heretofore, 
but the author has specimens taken on California holly or Christmas 
berry in Sespe Canyon during ilarch and May, 1915, by S. H. Essig 
and C. P. Clausen. 

m. Prociphilus venafuscus Pati'h 

Patch, Ent News, vol. 20, p. 319, 1909. Pemphigus (orig. desc). 

Essig, Pom. Jour. Ent., vol. 3, p. 553, 1911. Pemphigus fraxini-dipetalae 
n.sp. (orig. desc). 

Essig, Pom. Jour. Ent., vol. 4, p. G99, 1912. Pempliigus fraxini-dipetalae 
Essig (list). 

C'hilds, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 220, 1914. Pemphig-iis 
fraxini-dipetalae Essig (list). 

Wilson, Trans. Am. Ent. Soc, vol. 41, p. 85, 1915. Prociphilus fraxini- 
dipetalae (Essig) (note). 

Davidson, Jour. Econ. Ent., vol. 8, p. 421, 1915. Prociphilus fraxini- 
dipetalae (Essig) (list). 

Baker, Jour. Agr. Ees., vol. 6, pp. 1118-1119, 1916 (desc. notes, synonymy). 

Becords. — Fraxinus dipetala; Santa Paula (Essig), Contra Costa and Santa 
Clara counties (Davidson): F. oregona: Oregon (Wilson); Berkeley, April, 1915: 
Aesculus calif ornicus ; Sacramento (Childs) : Pscudotsvga taxifolia; Oregon (Wil- 
son). 

Occasionally this verj- large aphid is found infesting the leaves 
of ash in the San Francisco Bay region and in the mountains of 
southern California. In early summer it leaves the ash, and according 
to Wilson infests the roots of Douglas fir in Oregon. At one time 
Leroy Childs found a few specimens on buckej^e in the vicinity of 
Sacramento, but it is probable that these were accidental there. 



A SYNOFSIS OF THE AFUIDIDAE 147 

Group Schizoneurina Liehteusteiu 

This group as considiTcd by JMordwilko contains tlie following 
genera: Loicia Lieht., Colopha Monell, Pachypappa Koch, Schizoneura 
Hartig, Anoecia Koch, and Mindnnta Kocli. Tullgren places in his 
tribe Schizoneurina the two genera, Schizoneura Hartig, and Tetra- 
nrura Hartig. Pachypappa Koch he places in his tribe Pemphigina, 
and he has a separate tribe for each of the genera Anoecia Koch and 
Mindarus Koch, calling them respectively tribe Anoeciina and tribe 
Jlindarina. Below is a translation of Mordwilko's key. 

1. Wings laid flat on back when at rest Lbwia Licht. 

— Wings held roof -like when at rest 2 

2. Stigma of forewings trapezoidal in shape, reaching only to the beginning of 

the curve around the end of the wing, never extending to the tip of the 
wing. Eadial vein originating from the posterior exterior corner of the 

stigma 3 

— ■ Stigma linear, very long, reaching to the wing tip on the front side of the 
wing, and even following the backward curve of the exterior side of the 
wing to some extent. Radial vein starting almost at the beginning to the 
interior edge of the stigma. Sexual forms with beaks Mindarus Koch 

3. Hind wings with one transverse vein Colopha Monell 

— Hind wings with two transverse veins 4 

4. Both transverse veins originating from the same point on the longitudinal 

veins Pachypappa Koch 

— Transverse veins of hind wings originating separately 5 

5. Bodies of apterous and alate forms with little hair, and covered at least on the 

dorsum of the abdomen with waxy powder. Cornicles pore-like (point -like). 
Sexual forms without beaks Eiiosoma Leach 

— Bodies of apterous and alate forms very hairy and not covered with waxy 

powder or granules (only the stem mothers are weakly pulverulent). Cor- 
nicles comparatively large, tuberculate (cone-like). Sexual forms with 
beaks .' Anoecia Koch 

The genera Lowia Licht., Pachypappa Koch, and Anoecia Koch 
are not represented in California. Colopha Monell and Mindarus 
Koch are both represented by their type species. It has been proven 
that Eriosoma Leach has priority over Schizoneura Hartig, so that 
genus is now known by that name. It is represented in California by 
three or four species at present. 



148 MISCELLANEOUS STUDIES 

42. Genus Colopha Jlonell 

Monell, Can. Ent., vol. 9, p. 102, 1877. Type Byrsocrypta -ulmicola Fitch. 

172. Colopha ulmicola (Fitch) 

Fitch, Eept. Ins. N. Y., vol. 4, p. 63, 1858. Byrsocrypta (orig. desc). 
Davidson, Jour. Eeon. Ent., vol. 2, p. 299, 1909 (list). 
Patch, Maine Agr. Exp. Sta., Bull. 181, 196, 1910 (desc). 

Record. — Ulmus sp. ; Stanford University (Davidson). 

Davidson recorded this species from elm at Stanford University in 
1909. Since then it has not been found again. 

■43. Genus Eriosoma Leach 

Leach, Trans. Hort. Soc. London, vol. 3, p. 54, 1820. Type Aphis lani- 
gerum Hausman. 

Until quite recenth' tliis genus has been known as Schizoneura 
Hartig, but as Baker^- has pointed out, the name Eriosoma has 
priority-. In California there are three distinct species represented, 
with a possible fourth. One of these is known only on elm, one on 
apple (and elm), and one on pear (and elm). 

The following key to the fall migrants is adapted partially from a 
table of Baker and Davidson.'^ 

1. Body naked except caudal segment. Distal sensoria of V and VI with fringe. 

languinosa (Hartig) 

— Body with some woolly covering. Distal sensoria without fringe 2 

2. Wing veins narrow without brown margins. Ill longer than IV, V, and VI 

together lanigerum (Haus.) 

— Wing veins broad with bro^vnish margins. Ill not so long as IV, V, and VI. 

americana (Riley) 

178. Eriosoma americana (Riley) 

Riley, U. S. Geol. Surv., Bull. 5, p. 4, 1879. Schizoneura (orig. desc). 
Clarke, Can. Ent., vol. 35, p. 248, 1903. Schizoneura (list). 
Patch, Maine Agr. Exp. Sta., Bull. 220, p. 268, 1913. Schizoneura (desc 
note). 

Records. — Ulmus americana; Berkeley (Clarke) ; Walnut Creek, June, 1915 
(Davidson) ; Palo Alto, May, 1915. 

This leaf-curling aphid of the American elm is found in the San 
Francisco Baj^ region, and in some cases is very abundant. In May 



32 Baker, A. C, The woolly apple aphis, U. S. Dept. Agr., Office Sec'y, Report 
101, pp. 11-12, 1915. 

33 Baker, A. C, and Davidson, W. M., Woolly pear aphis. Jour. Agr. Res., 
vol. 6, p. 358, 1916. 



A SYNOPSIS OF THE JPHIDIDAE 149 

and June, 1915, it was especially so on a row of elms on the campus 
of Stanford University. At that time stem mothers, nj-mphs, and 
alate spring migrants were present in the galls. By the la.st of June 
all of these had flown away, leaving the galls empty. According to 
Baker elm is the only host plant of this species. 



174. Eriosoma lanigerum (Hausman) 

Hausman, Mag. Ins., vol. 1, p. 440, 1802. Aphis (oi-ig. desc). 
Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. ScUizoneum (list). 
Daviflson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Scldzoneura (list). 
Baker, U. S. Dept. Agr., Office See 'y, Report 101, pp. 11-16, 1915 (desc. 
and biology). 

Secord. — Pyrus mains, throughout the state. 

Wlierever apple trees are found in the state this woolly aphis is 
also found ; the white mas.ses on the trunks and leaves being very con- 
spicuous, the colonies on the roots more injurious but less conspicuous. 
In California only the apple lias been found to be attacked. The 
winter is passed by young nymphs on the roots. As the warmer 
weather of spring comes these migrate up the trunks and out on 
the branches and twigs. Here they feed throughout the summer. In 
tlie fall there is a downward migration, and occasionally a fall 
migrant is seen. Whether or not these fly to elms as in other parts of 
the countrj-, is not known, but none have ever been observed on elm. 



175. Eriosoma languinosa (Hartig) 

Hartig, Zeitschr. Ent., vol. 3, p. 359, 1841. Aphis (orig. desc). 

Baker and Davidson, Jour. Agr. Ees., vol. 6, pp. 351-360, 1916. E. pyricola 

n.sp. (desc). 
Baker and Davidson, Jour. Agr. Roa., vol. 10, pp. 65-74, 1917. E. pyricola 

B. & D. (desc. and biology). 
Becords. — Pyrus communis, XJlmus campestris ; central California. 

In 1916 Baker and Davidson described a species of Eriosoma that 
attacks the roots of pears throughout the central part of the state, 
naming it E. pyricola. Later Davidson found that a species common 
on IJlmus campestris was the alternate form of this species. This elm 
form checks up very favorably witli specimens of E. languinosa Hartig 
from Europe, and is undoubtedly identical. Thus the name pyricola 
will have to be dropped in favor of langninosa. These elm galls are 
of a rather peculiar shape, and, as Patch writes, they have the appear- 
ance of a bonnet. 



150 MISCELLANEOUS STUDIES 

44. Genus Mindarus Koch 
Koch, Die Pflanzenlause, p. 277, 1857. Type M. abittiiius n.sp. 

176. Mindarus abietinus Koch 

Koch, Die Pflanzenlause, p. 278, 1837 (orig. desc). 

Clarke, Can. Ent., vol. 35, p. 248, 1903. Schisoiieura panicola Thos. (list). 

Patch, Maine Agr. Exp. Sta., Bull. 182, p. 242, 1910 (desc). 

Records. — Piniis radiata ; Berkeley, Palo Alto (CHarke) : Abies cilicia ; Stan- 
ford University, May, 1915. 

Thi.s aphid, easily recognizi'd by tliu extremely long stigma of the 
fore wings, has been fonnd in the San Francisco Bay region infesting 
the shoots of Monterey pine and Cilieian fir. 



Group Vacunina ]\Ic»rdwilko 

This group contains but two genera, Vactoia Heyden and (rlyphin-a 
Koch. Mordwilko does not recognize Ghjphina as distinct from 
Vacuna, althongh Tnllgi-en does. The latter separates the two genera 
as follows : 

1. Last abdominal tergite formed into a knob-shaped tail. Integument bare, 

and at most partially set with short lancet-shaped hairs Vacuna Heyd. 

— Last abdominal tergite half-moon shaped, strongly swollen, but scarcely, 
if at all, separated from the base. Integument set with stiff bristle-like 
hairs and in apterous females with grain-like elevations ....Glyphina Koch^i 

45. Genus Vacuna Ileyden 

Heyden, Ent. Beitr., vol. 2, p. 289, 1837. Type Aphis drjiopJiila Sflirank. 

177. Vacuna dryophila (Schrank) (?) 

Schrank, Fauna Boica, vol. 1, p. 113, 1801. Aphis (orig. desc). 
Davidson, Jour. Econ. Ent., vol. 7, p. 128, 1914. Chaitophorus sp. (desc). 
Davidson, Jour. Econ. Ent., vol. 10, p. 290, 1917 (desc). 

Record. — Quercns lob at a ; Walnut Creek (Davidson). 

Recently Davidson described this species from specimens taken on 
valley oak in Contra Costa County, where he had observed it for three 
years. The single alate female he has taken does not appear identical 
with European specimens of V. dryophila. so he lists the species under 
this name provisionally. 



34 This genus is not represented in California. 



A SYNOPSIS OF THE APHIVIDAE 151 



Subfamily Phylloxerinae Dreyfus 

This subfamily consists of two groups, the Chermisina and the 
Phylloxerina. Below is a key to these two groups taken from Van 
der Goot : 

1. Body alwaj's with wax glands. Antennae of adults three-jointed, seemingly 
five-jointed, with three large sensoria. Gonapophyses appearing as three 

short lips. Sexuales dwarfed, with beak Group Chermisina 

— Body usually without wax glands. Antennae of adults three-jointed, with two 
large sensoria. Gonapophyses seem to be lacking. Sexuales dwarfed, with- 
out beak Group Phylloxerina 



Group Chermisina Borner 

This groiip consists of three genera, Pineus Shimmer, Cnapholodes 
Macq., and Chcrmcs Linn, as it is generally considered, although some 
authors add more, as Gillcttca Del Guercio and Gucrcioja Mordw. In 
California but one of these genera is represented, and that hy but 
two species. 



46. Genus Chermes Linnaeus 

Linnaeus, Syst. Nat., vol. 10, IT.'iS. Type Chermes sambuci Linn. 

178. Chermes cooleyi Gillette 

Gillette, Proc. Acad. Nat. Sci. Phila., vol. 69, p. 3, 1907 (orig. desc). 
Davidson, Jour. Eeon. Ent., vol. 2, p. 299, 1909. C. coweni Gill. (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. C. coweni Gill. (list). 
Brannigan, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 285, 1915 (list). 

Records. — Pseudotsvga taxifolia, Pinus pinea ; San Francisco Bay region, Sac- 
ramento Valley. 

This species was first reported in California by Davidson, wlio 
found it on Douglas fir at Stanford University. Essig lists it from 
San Francisco, San Mateo, and Santa Clara counties on Douglas fir. 
In 1915 it was reported twice, once in Sacramento on Douglas fir, and 
once on Italian stone pine. The author has specimens from E. J. 
Vosler taken in Sacramento where it was found infesting the twigs 
and needles of Italian stone pine. Only the apterous females were 
present, however. 



152 MISCELLANEOUS STUDIES 



179. Chermes pinicorticis Pitch 

Fitch, Trans. N. Y. State Agr. Soc, vol. 14, p. 971, 1855. Coccus (orig. 

desc). 
Storment, 20th Ann. Eep. Illinois St. Ent., appendix, 1898 (desc). 
Da\'idson, Jour. Econ. Ent., vol. 2, p. 299, 1909 (list). 
Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910 (list). 

Becord. — Finns pinaster maritima; Stanford University (Davidson). 

This species, which is uuknown to the author, was reported as 
present at Stanford University on Pimis pinaster mMritima, where 
it was so abundant as to sometimes kill the young trees. For a com- 
plete description see Storment 's jjaper listed above. 



Group Phylloxerina Borner 

There are two genera in tliis tribe, as considered by Borner and 
Mordwilko, although tlie American authors have generally taken cog- 
nizance of but one, namely, Phylloxera Boyer. Below is a key from 
Mordwilko to these genera. 

1. Neither wingless females nor any other forms secreting any -naxj material. 

Phylloxera Boyer 
— Wingless females secreting a waxy powder Phylloxerina Borner 



-t7. Geiins Phylloxera Boyer 

Boyer de Fon.scolmbe, Ann. Ent. Soc. France, vol. 3, p. 222, 1834. Type 
P. quercus Boyer. 

ISO. Phylloxera vitifoliae Fitch 

Fitch, Eept. Ins. N. Y., vol. 1, p. 58, 1855 (orig. desc). 

Planchon, C.-R. Acad. Sci. Paris, vol. 67, pp. 588-594, 1868. P. vastatrix 

(desc). 
Clarke, Can. Ent., vol. 35, p. 248, 1903. P. vastatrix Plan (list). 
Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. P. vastatrix Plan. (list). 

Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. P. vastatrix Plan. (list). 
Records. — Grape; Central and Northern California. 

This is the only species of this genus reported in California. It 
is one of the most destructive species of plant lice in this section of 
the country, having in its time practically wiped out the grape indus- 
try of Santa Clara Valley, and of many other parts of the state. It 
seems that in California this species infests the roots only of the grape, 
the forms that produce the leaf galls in the eastern parts of the 
country not being found here. 



A Sl'NOPSIS OF THE APEIDIDAE 153 



48. Genus Phylloxerina Borner 

Borner, Arbeiter aus d. kais. biol. Anst. f. Land- und Porstwirtschaft, 
vol. 6, pp. i-v, 81-320, 1908. Type Phylloxera salicis Liun. 

Thi.s genus is represented in California by two species, one found 
on the stems of cottonwood {Pupulus sp.) and the other on the stems 
and exposed roots of willow {Salix sp.). 



181. Phylloxerina popularia (Pergande) 

Pergrande, Proc. Davenport Acad. Sci., vol. 9, p. 266, 190-t. Phylloxera 

(orig. desc). 
Davidson, Jour. Econ. Ent., vol. 8, p. 420, 1915. Phylloxera (list). 

Sccords. — Populus spp.; Walnut Creek (Davidson), Merced (Beers). 

The only report of this species in California is the one of Davidson 
who found it on Populus frcmonti and Populus trichocarpa at "Walnut 
Creek. On October 14, 1915, A. A. Beers of Merced sent some speci- 
mens to the author from balm of Gilead {Populus halsamifera) in 
Merced. These were all apterous females, and were found in great 
masses of white wax on the smaller branches and twigs. These reports 
are the onlj^ ones since its original report from Texas and Louisiana 
bv Pergande. 



182. Phylloxrina salicola (Pergande) 

Pergande, Proc. Davenport Acad. Sci., vol. 9, p. 267, 1904. Phylloxera 

(orig. desc). 
Davidson, Jour. Econ. Ent., vol. 8, p. 419, 191.5. Phylloxera (list). 

Becords. — Salix spp.; Walnut Creek (Davidson); Pasadena (Smith). 

This species was also reported from Walnut Creek by Davidson 
on arroyo willow {Salix lasiolepis) where he found it on the stems 
and exposed roots. On October 13, 1915, A. G. Smith sent the author 
specimens from an ornamental willow {Salix sp.) in Pasadena, where 
he found it very abundantly that fall. The specimens were all 
apterous females, and M'ere found in the midst of considerable masses 
of wax. This species has only been reported from Illinois, District 
of Columbia, and California. 



154 MISCELLANEOUS STUDIES 



APPENDIX 1 
Keys to the Genera and Tribes of APHIDIDAE 

BY 

P. VAN DER GOOT, 1913 

SubfamUy APHIDINAE 

1. Antennae seven-jointed (better six-jointed). The last true joint with a dis- 

tinct, more delicate continuation (terminal process). This continuation 
almost as long as, or even much longer than the last segment; if shorter, 
the Cauda is distinctly wart-shaped, and the number of rudimentary gona- 
pophj-ses is always two. Cornicles almost always well formed and clearly 
projecting. Wings with twice-branched cubitus, only once-branched in 
exceptional eases 2 

— Antennae mostly six-jointed, the last joint with a short projection, this being 

usually distinctly shorter than half the last segment. Cornicles scarcely 
projecting, very often only appearing as pores or entirely absent. Wings 
with a simple or once-branched cubitus 5 

2. Cauda wart-like, occasionall.v not so, or scarcely separated, but then the number 

of rudimentary gonapophyses is always distinctly two 3 

— Cauda sickle-shaped or knobbed, not wart-like, only very seldom absent. Rudi- 

mentary gonapophyses always three Siphonophorina 

3. Cornicles very long, almost cylindrical. Rudimentary gonapophyses tlirce. 

Drepanosiphina 

— Cornicles very sliort, somewhat clubbed. Rudimentary gonapophyses two or 

four 4 

4. Xumber of rudimentary gonapophyses four. Body never with long clubbed 

hairs Chaitophorina 

— Number of rudimentary gonapophyses two. Body often with kiioliI)ed hairs. 

Tarsi always with two pulvillae [Haftlappehen] Callipterina 

5. Cauda wart-like 6 

— Cauda not wart-like, usually absent 7 

6. Anal plate bilobed. Sensoria of alate females linear Hormaphidina 

— Anal plate simple. Sensoria of alate females circular Vacunina p.p. 

7. Cauda distinctly sickle-shaped Mindarina' 

— - Cauda only scarcely or not at all separated 8 

8. Antennae five-jointed. Cornicles very short, only slightly projecting. Body 

without distinct wax gland groups Vacunina p.p. 

— Antennae six-jointed, those of the apterous forms often only four- or five- 

jointed. Cornicles often only pores or entirely lacking. Body often with 
wax gland 9 

9. Body with long, mostly fine hairs; without distinctly facetted wax gland 

plates. Primary sensoria almost always without hairy edges 10 

— Body naked; very often with distinctly facetted wax-gland plates. Primary 

sensoria often with hairy edges 11 

10. Rudimentary gonapophyses three. Wings mostly with twice-branched cubitus. 

Cornicles always prominent Lachnina 

— • Rudimentary gonapophyses none. Wings with simple or once-branched cubitus. 

Cornicles often absent Anoeciina 



A SYNOPSIS OF THE APHIDIDAE 155 

11. Rudimentary gonapopliyses three. Facets of wax-glanil plates almost equal- 
sized. Wings with simple cubitus. Sensoria of alate forms long oval, net 
linear PempMgina 

— ■ Rudimentary gonapophyses none. Wax gland plates always with at least 
one large central facet. Sensoria of alate forms linear. Wings with simple 
or once-branched cubitus Schizoneurina 

Subfamily CHEBMISINAE 
1. Rudimentary gonapophyses appearing as three short cones. Wax glands 
almost alwa}'s present Chermislna 

— Rudimentary gonapophyses seemingly lacking. Wax glands mostly absent. 

Phylloxerina 

Group SiPHONOPHORINA 

1. Apterous forms with a few sensoria on the third antenna! segment. Autennal 

tubercles usually well formed. Body almost never with lateral tubercles, 
in any case these are never formed on the seventh abdominal segment -.. 2 

— Apterous forms without Sensoria on the third antennal segment. Anteunal 

tubercles often small or absent. Body with lateral tubercles i 

2. Cornicles almost cylindrical, or rarely somewhat swollen on the side, but then 

the body is covered with capitate hairs 3 

— Cornicles distinctly clavate. Body almost bare, never with capitate hairs. 

Rhopalosiphum Koch 
Type Amphoropliora anipuUata Buckton. 

3. Body of apterous forms with long capitate hairs. First antennal joint 

drawn out, somewhat tooth-shaped on the inner side Myzus Passerini 

Type Aphis riiis Linn. 

— Body of apterous forms bare or without capitate hairs. First antennal joint 

never drawn out, tooth-like Macrosiphum Passerini 

Type Aphis millifolii Fabr. 
i. Body of apterous forms with capitate hairs. First antennal joint more or 

less toothed on inner side Capitophorus n.gn. 

Type Fhorodon carduinixm Walker. 
— • Body of apterous forms without capitate hairs. First antennal joint not 
toothed 5 

5. Body with many long delicate hairs. Cornicles short, somewhat swollen. 

Cladobius (Koch.) Pass. 
Type Aphis populea Kalt. 

— Body bare or almost so fi 

6. Cornicles almost as long or longer than cauda 7 

— Cornicles much shorter than cauda Ifi 

7. Cornicles always distinctly clavate Siphocoryne Pass. 

Type Aphis avenae Fabr. 

— Cornicles cylindrical or conical S 

8. Antennal tubercles well formed, very distinctly toothed on the inner side. 

Tubercles on the side of the body always absent 9 

— Antennal tubercles mostly small or lacking, never distinctly toothed. Body 

often with lateral tubercles 10 

9. Antennal tubercles very strongly toothed, the first joint being distinctly 

toothed on the inner side Phorodon Pass. 

Type Aphis humuli Schr. 
— • Antennal tubercles only slightly toothed, first antennal joint being rounded 

or flat on the inner side, never toothed Ovatus n.gn. 

Tj'pe Ovatus mespili v. d. G. 



15G MISCELLANEOUS STUDIES 

10. Antennal tubercles well formed, strongly rounded on the inner side. 

Type Aphis cerasi Fabr. '^ ' 

— Antennal tubercles small or lacking, never drawn out distinctly on inner 

side 11 

11. Body with small tubercles on the middle of the seventh and eighth abdominal 

segments, and often also on the head and prothorax Dentatus n.gn. 

Type Aphis sorbi Kalt. 

— Body without tubercles on the middle of the seventh and eighth abdominal 

segments 12 

12. Cubitus of fore wing only once-branched Toxoptera Koch 

Type Toxoptera graminum (Eond.). 

— Cubitus of fore wing always twice-branched. Body often with lateral tuber- 

cles 13 

13. Cornicles short, always distinctly conical. Cauda very short, broad with 

rounded tip, usually approximately the length of the cornicles, or entirely 
lacking. Lateral tubercles lacking or only indistinctly formed on the an- 
terior abdominal segments 15 

— Cornicles long, almost cj-lindrical. Cauda sickle- or club-shaped, usually dis- 

tinctly shorter than cornicles ..14 

14. Body long without lateral tubercles. Front often with a very distinct tubercle 

in the middle Myzaphis n.gn. 

Type Aphis rosarnm Walker. 
— • Body more rounded, with lateral tubercles. Front usually flat, never with a 
distinct tubercle Aphis Linn. 

Type Aphis rumicis Linn. 

15. Cauda distinctly separated, almost as long as broad Brachycaudus n.gn. 

Type Aphis myosotidis Koch. 

{Aphis cardui Linn, belongs in this genus.) 

— Cauda lacking or scarcely separated, much shorter than broad ...Acaudus n.gn. 

Type Aphis lychnidis Linn. 

16. Cornicles distinctly longer than broad. Cauda usually not conical 17 

— • Cornicles extremely short, scarcely projecting, cylindrical, usually nearly as 

long as broad. Cauda always conical with broad base 19 

17. Cornicles only a little longer than broad, distinctly conical. Cauda sickle- or 

club-shaped Longicaudis n.gn. 

Type Hijalopterus trirhodus (Walker). 

— Cornicles cylindrical, at least twice as long as broad 18 

18. Body with lateral tubercles on first and seventh abdominal segments. Cauda 

small, club-shaped Hyalopterus Koch 

Type Aphis pruni Fabr. 

— Body without lateral tubercles on first and seventh abdominal segments. Cauda 

conical Semiaphis n.gn. 

Type Aphis carotae Koch. 

19. Body long, without lateral tubercles. Antennae short, at the most about half 

the length of the body Brachycolus Buckton 

Type Brachycolus stellariae (Hardy). 

— Body oval with lateral tubercles on prothorax, first and seventh abdominal 

segments. Antennae at least about three-fourths as long as the body. 

Type Aphis thalictri Koch. J v 'S • 

Group Drepanosiphina 
Genus Drepanosiphum Koch. Type Drepanosiphum platanoides Schrank. 



A SYNOPSIfi OF THE APHIDWAE 157 

Group Callipterina 

1. Antennae six-jointed. Cornicles merely pores. Body always with wax 

glands Phyllaphis Koch 

Type Phyllaphis fagi (Linn.). 
— • Antennae seven-jointed, the terminal process at least one-half .as long as the 
preceding joint. Cornicles always distinctly projecting. Body almost 
always without wax glands, the.se always of similar shape 2 

2. Seventh antennal joint distinctly longer than sixth 3 

— Seventh antennal joint only as long as, or shorter than sixth 6 

3. Cornicles but slightly projecting. Antennae curved as in beetles. 

Bradyaphis Mord. 
Type Bradyaphis antennata (Kalt.). 

— Cornicles distinctly prominent. Antennae straight 4 

4. Anal plate only slightly emarginate, never bilobed. Body with tolerably stiff 

hairs, these are never capitate. Apterous forms always with sensoria on 

third antennal joint Callipterinella n.gn. 

Type Callipteriis hctularins Kalt. 

— Anal plate distinctly bilobed. Body bare or with capitate hairs 5 

5. Apterous forms without sensoria on third antennal joint. The body always 

with capitate hairs Callipterus Koch 

Type Callipterus coryli (Goetze). 

— Apterous forms with a few sensoria on third antennal joint. Boily with dis- 

tinct tubercles Tuberculatus Mord. 

Type Tuberculatus hetulicolus (Kalt.). 

6. Anal plate distinctly bilobed S 

— Anal plate always simple 7 

7. Cauda wart-like, distinctly separated from base. Apterous forms without 

sensoria on third antennal joint CaUipteroides Mord. 

Type Callipterus hetulae Koch. 

— Cauda scarcely visible. Sensoria present on third antennal joint of apterous 

forms Symydobius Mord. 

Type Symydobius ohlongus (Heyden). 

8. Seventh antennal joint nearly as long as the sixth. Wings with only very 

small black spots at the tip of the veins Subcallipterus Mord. 

Type Callipterus alni (Fabr.). 

— Seventh antennal joint nearly half as long as sixth. Wings black spotted. 

Pterocallis Pass. 
Type Pterocallis tiliae (Linn.). 

Group Chaitophorina 

1. Body with long delicate hairs. Antennae seven-jointed. Cornicles well de- 

veloped 2 

— Body with short thorn-like hairs. Antennae six-jointed, the terminal process 

always distinctly longer than the preceding joint. Cornicles only slightly 

projecting Sipha Passerini 

Type Sipha glyceriae (Kalt.). 

2. Tarsi with two " Haf tliippchen " [i.e., the empodial hair is spatula-like]. 

Chaltophorinella n.gn. 
Type Chaiiophorus testudinntus (Thornton). 

— Tarsi without " Haftliippehen " [i.e. the empodial hair is bristle-like]. 

Chaltophorus Koch 
Type Chaiiophorus leucomelas Koch. 



158 MISCELLANEOUS STUDIES 

Group Lachnina 

1. Wings usually with twice-branched cubitus, the radius always straight. Cauda 

not at all or only slightly separated Laclinus 111. 

Type Lachnus juniperi De Geer. 

— Wings with once- or twiee-branchel cubitus and with a curved radius ; the mem- 

brane usually with dusky markings. Cauda usually slightly separated 2 

2. Beak distinctly longer than the body, strongly retractile. Cubitus but once- 

branched, the wings only slightly darkened Stomaphis Buckton 

Type Stomaphis quercus (Linn.). 

— Beak clearly shorter than body and only slightly retractile. Wings beautifully 

spotted with dark brown 3 

3. Cubitus twice-branched Dryobius Koch 

Type Dryobius croaticus Koch. 

— Cubitus once-branched Schizodryobius n.gn. 

Type Laclinus exsiccator Hart. 

Tribe ANOECIINA 

1. Hind tarsi elongate Trama Heyden 

Type Trama radicis Koch. 
— • Hind tarsi not elongate 2 

2. Cubitus once-branched. Cornicles present, quite prominent. Margin of body 

with peculiar non-faceted "wax-gland" (?) plates Anoecia Koch 

Type Anoecia corrii (Fabr.). 
— ■ Cubitus not branched. Cornicles absent. Wax gland plates not present. 

TuUgrenia v. d. G. 
Type TuUgrenia phaseoli (Pass.). 

Tribe HORMAPHIDINA 

1. Antennae always five-segmented. The fronds almost without exception with 

two little horns. Cubitus once brandied Cerataphis Lieht. 

Type C. lataniae Boisd. 
— • Antennae of the apterae often only three-segmented. Fronds without protuber- 
ances. Cubitus simple Hamamelistes Schim. 

Type H. ietulae Mordw. 



A SYNOPUla OF THE APHIDIDAE 159 



APPENDIX 2 
Host Plant List op California APHIDIDAE^^ 

Abies (fir) 

4.5. Lachnus fcrrisi Swain 
47. Lachnus occidentalis Dvdn. 
176. Mindaru-s obietinus Koch 
AhtUilon (Indian mallow) 

146. Aphis senecio Swain 
104. Slwpalosiphum pcrsicac (Sulz.) 
Acer (maple, box elder) 

5. Drepanaphis acerifolii (Thomas) 
4. Drepannsiphum plaiannides (Sehrank) 
33. Thomtisia negundinis (Thomas) 
Achillea (yarrow) 

79. Macrosiphuin solanifolii (Ashmead) 
Acgopodium (goutweed) 

108. Siphocorync capreae (Pabr.) 
Aesculus (California buckeye) 

88. Myzus circumflexus (Buckton) 
171. Prociphilus venafuscus Patch 
Alder, see Alnus 
Alfalfa, see Mcdicago 
Alfilerilla, see Erodium 
Alisma (water plantain) 

156. Siphocoryne ni/mphaeae (Linn.) 
Almond, see Prunus 
Alnus (Alder) 

9. Eucallipterus jlava (Davidson) 
8. Euceraphis gillettei Davidson 
11. MyzocaUis alnifoliae (Fitch) 
Alopecurus (foxtail) 

68. Macrosiphum granarium (Kirby) 
88. Myzus circumflexus (Buckton) 
Althaea (hollyhock) 

121. Aphis eunnomi Fabr. 
Alum root, see Heuchera 



35 In the following list only the generic and common names of the plants are 
employed, the various species of plants being omitted. Although in certain cases 
aphids are restricted to certain species, as Eriosoma languinosa Hartig on Pyrus 
communis but not on Pyrus malus, these are in the minority. The botanical 
names are taken from the following works, with preference as in the order listed : 

Bailev, L. H., Standard cyclopedia of horticulture, vols. 1-6, New York, Mac- 
millan, 1914-1917. 

Eobinson, B. L., and Fernald, M. L., Gray 's New manual of botany, ed. 7, 
Cambridge, Harvard University, 1908. 

Jepson, W. L., A flora of western middle California, ed. 2, San Francisco, Cun- 
ningham, 1911. 

Abrams. LeRoy, Flora of Los Angeles and vicinity, Palo Alto, Stanford Uni- 
versity Press, 1904. 



160 MISCELLANEOUS STUDIES 

Amaraiithus (pigweed) 

123. Aphis gossypii Glover 

132. Aphis middletonii Thomas 

104. Shopalosiplium persicae (Sulz) 

163. Trifidaphis radicicola (Essig) 
Amhrosia (ragweed) 

146. Aphis scnecio Swain 
77. Macrosiphum rudbeckiae (Fitch) 
Ampelodesma 

68. Macrosiphum granarium (Kirby) 
Amsiiiclcia (amsinckia) 

146. Aphis seneoio Swain 

104. Bhopalosiphiim persicae (Sulz.) 
Angelica (angelica) 

109. Aphis angi'licae Koch 

115. Aphis cari Essig 

108. Siphocoryne capreae (Fabr.) 
Anise, Wild, see Carum 
Anthemis (chamomile) 

121. Aphis euonomi Fabr. 
146. Aphis senecio Swain 
123. Aphis gossjipii Glover 

Apple, see Pyrus 
Apricot, see Prunus 
Aquilegia (columbine) 

85. Mysus aquilegiae Essig 
Arbor vitae, see Thuja sp. 
Arbutus (mailrone, strawberry tree) 

103. Hhopalnsiphum nervatuvi Gillette 
Arctostaphylos (maiizanita) 

1. PhyUapliis coiveni (Cockerell) 

103. Bhopulosiphum nervatum Gillette 
Artemisia (sagebrush, oldman, California mugAvort, etc.) 

122. Aphis frigidae Oestlund 
131. Aphis medicaginis Koch 
137. Aphis oregonensis Wilson 
146. AjMs senecio Swain 

61. Macrosiphum artemisiac (Fonsc.) 

62. Macrosiphum artemisicola (Williams) 
72. Macrosiphum ludovicianiae (Oestlund) 

Artichoke, see Cynara 
Arundinaria (bamboo) 

12. MyzocaUis arundicolens (Clarke) 

13. Myzocallis arundinariae Essig 
Arundo (giant reed) 

12. MyzocaUis arundicolens (Clarke) 

13. Mjisocallis arundinariae Essig 
Asclepias (milkweed) 

123. Aphis gossypii Glover 
135. Aphis nerii Fonsc. 

102. Rhopalosiphum lactucae (Kalt.) 



A SYNOPSIS OF THE APHIDIDAE 161 

Ash, see Fraxiinis 

Arparagus (asparagus, smilax, asparagus feru) 

123. Aphis gossypii Glover 
88. Myzus circamflexus (Buekton) 
Aster (aster) 

132. Aphis middletonii Thomas 

146. Aphis senccio Swain 
Astragalus (loco weed) 

131. Aphis medicaginis Koch 
Atriplex (oraehe) 

147. Aphis tetrapteralis Coekerell 

79. Macrosiphum solanifolii (Ashmead) 
Avocado, see Persca 
Avena (oats) 

111. Aphis avenae Fabr. 

(i8. Macrosiphum granarium (Kirby) 
105. Uhopalosiphum rhois Monell 
Baccharis (groundsel) 

146. Aphis senecio Swain 

63. Macrosiphum baccharadis (Clarke) 

77. Macrnsiplivm rudheclme (Fiteh) 
104. Uhopalosiphum persicae (Sulz.) 
Bamboo, see Arundinaria, Bamhusa, and Phyllostachys 
Bamhusa (bamboo) 

12. Mrtzocallis arundicolens (Clarke) 
Banana, see Musa 
Barberry, see Berberis 
Barley, see Hordrum 
Basswood, see Tilia 
Bean, see Pliaseolus 
Bean, Blackeye, see Vigna 
Bean, Broad, see Vicia 
Beech, see Fagus 
Beet, see Beta 
Begonia (begonia) 

123. Aphis gossypii Glover 
Bell, fairy, see Dipsorum 
Berberis (barberry) 

154. Liosomaphis herberidis (Kalt.) 
Beta (beet, sugarbeet) 

124. Aphis gossypii Glover 
164. Pemph'gns betae Doane 

Betula (birch) 

6. Calaphis betulaecolens (Fitch) 
27. CalUpterinella annulata (Koch) 

7. Euceraphis betulae (Koch) 
Birch, see Betula 

Blackberry, see Subus 
Bougainvillea (bougainvillea) 

104. Uhopalosiphum persicae (Sulz.) 
Boxelder, see Acer 



162 MISCELLANEOUS STUDIES 

Brassica (cabbage, mustard, turnip, etc.) 

112. Aphis hrcissicac Linn. 

144. Aphis pseudohrassicae Davis 

166. Pemphigus popuU-transversiis Riley (?) 

102. Ehopalosiphum lactucac (Kalt.) 

104. BhopalosipMim I'^rsicue (Sulz.) 

Broom, see Cytisus 

Buckeye, California, see Aesculus 

Buekton, see Bhamnxis 

Bur clover, see Medicago 

Buttercup, see Sanuncuhis 

Cabbage, see Brassica 

Calendula (marigold) 

113. Aphis calendulicola Monell 
121. Aphis euonomi Fabr. 
146. Aphis senecio Swain 

California buckeye, see Aesculus 
California holly, see Heteromeles 
California mugwort, see Artemesia 
California poppy, see Esclischoltzia 
California sagebrush, see Artemisia 
California tule, see Tjipha 
Calla, see Zanicdeschia 
Camellia (camellia) 

152. Toxoptcra auraiitii (Fonsc.) 
Canary grass, see Phalaris 
Cantaloupe, see Cucumis 
Capsella (shepard's purse) 

112. Aphis brassicac Linn. 

123. Aphis gossypii Glover 

141. Aphis pseudohrassicae Davis 

104. Ehopalosiphum persicae (Sulz.) 
Capsicum (pepper piraeuto) 

104. Ehopalosiphum persicae (Sulz.) 
Caragana (pea tree) 

131. Aphis medicaginis Koch. 
Carum (wild anise) 

115. Aphis cari Essig 

155. Siphocor]ine caprcae (Fabr.) 
Castanea (chestnut) 

15. My^ocallis castanicola Baker (davidsoni Swain) 
Catalpa (catalpa) 

123. Aphis gossypii Glover 

139. Aphis pomi de Gee'r 

104. Ehopalosiphum persicae (Sulz.) 
Cauliflower, see Brassica 
Ccanothus (mountain lilac) 

116. Aphis ceanothi Clarke 
Centaurea (taealste) 

130. Aphis marutae Oestlund 
Centranthus (red valerian) 

76. Macrosiphum rosae (Linn.) 
104. Ehopalosiphum persic-ae (Sulz.) 



A SYNOPSIS OF THE APHIDIDAE 163 

Chaerophyllum 

155. Siphocoryne capreae (Fabr.) 
Chamomile, see Anthemis 
Chaparral broom, see Baecharis 
Charlock, see Brassica 
Cheeseweed, see Malva 
Cheiranthus (wallflower) 

88. Myzus circumflexus (Buckton) 
Chenopodium (lamb's-quarters, pigweed) 

110. Aphis atriplicis Linn. 

123. Aphis gossypii Glover 

124. Aphis hederae Kalt. (?) 
164. Pemphigus betae Doane (?) 
104. Ehopalosiphum persicae (Sulz.) 

Clierry, see Prunus 
Cherry, wild, see Prunus 
Chestnut, see Castanea 
Chestnut, Horse, see AescnUis 
Chicory, see Chicorium 
Christmas berry, see Hcteromeles 
Chrysanthemum (chrysanthemum) 

56. Amphorophora latysiphon Davidson 

123. Aphis gossypii Glover 

146. Aphis senecio Suvain 

160. Coloradoa rufomaculata Wilson 

77. Macrosiphum rudheckiae (Fitch) 

78. Macrosiphum sanhorni Gillette 
Cichorium (chicory) 

71. Macrosiphum lactticae (Kalt.) 
Cicuta (water hemlock) 

155. Siphocoryne capreae (Fabr.) 
Cirsium (thistle) 

144. Aphis cardui Linn. 
CitruUus (watermelon) 

123. Aphis gossypii Glover 
Citrus (citrus, orange, lemon, etc.) 

118. Aphis cool'i Essig 

123. Aphis gossypii Glover 

131. Aphis medicaginis Koch 

79. Macrosiphum solanifolii (Ashmead) 
104. Ehopalosiphum persicae (Sulz.) 
152. Toxoptera aurantii (Fonsc.) 

Clarlia (clarkia) 

104. Ehopalosiphum persicae (Sulz.) 
Clewiatis (clematis) 

94. Myzus varians Davidson 
Clover, see Trifolium 
Clover, Sweet, see Melilotus 
Coffeeberry, see Ehamnus 
Columbine, see Aquilegia 
Compositae (various species) 

131. Aphis medicaginis Koch 

65. Macrosiphum chrysanthcmi (Oestlund) 

77. Macrosiphum rudbeckiae (Fitch) 



164 MISCELLANEOUS STUDIES 

Conium (poison hemlock) 

159. Siphocoryne pastinac<ie (Linn.) 
Convolvulius (morning glory) 

56. Amphorophora latysiphon Davidson 
123. Aphis gossypii Glover 
72. Macrosiphum ludovicianae (Oestlund) 
Corn, see Zea 
Coriius (dogwood) 

119. Aphis cornifoliae Fitch 
123. Aphis gossypii Glover 

Coryhis (hazelnut) 

16. Myzocallis coryli (Goetze) 

100. Bhopalosiphum corylinum Davidson 
Cotoneaster (cotoneaster) 

139. Aphis pomi de Geer 
Cotton, see Gossypium 
Cottonwood, see Popuhts 
Cow parsnip, see Heracleuin 
Cowpea, see Vigiia 
Cowslip, see Primula 
Crab apple, see Pyrus 
Cranesbill, see Geranium 
Crataegus (hawthorn) 

120. Aphis crataegifoliae Fitcli 
139. Aphis pomi de Geer 

Cruciferae (various spp. ) 

112. Aphis brassicae Linn. 

141. Aphis pscudobrassicae Davis 
Cucumber, see Cucumis 
Cucumis (cucumber, muskmelon, cantaloupe, etc.) 

123. Aphis gossypii Glover 
Cucurbita (squash, gourd, pumpkin, etc.) 

123. Aphis gossypii Glover 
66. Macrosiphum cucurhitae (Thomas) 
Cuprcssus (cypress) 

161. Cerosipha cuprcssi Swain 

90. Macrosiphum morrisoni Swain 
Currant, see Bibcs 
Cydonia (quince) 

139. Aphis pomi De Geer 
Cynara (artichoke) 

8fi. Myzus braggii Gillette 
C ynoglossum (houndstongue) 

104. Shopalosiphum persicae (Sulz.) 
Cypress, see Cupressus 
Cyrtomium (holly fern) 

162. Cerataphis lataniac (Boisd.) 
.58. Idiopterus neithrclepidis Davis 
88. Myzus cireumfiexus (Buckton) 

Cytisus (broom) 

146. Aphis senecio Swain 

104. Bhopalosiphum persicae (Sulz.) 



A SYNOPHIS OF THE APHIDIDAE ]65 

Dandelion, see Taraxamm 
Datura (jimson weed) 

123. Aphi^ gossypii Glover 
Deinandra 

79. Maerosiphwm solanifolii (Ashmead) 
Digitalis (foxglove) 

88. Myzus circumflexus (Buckton) 
Dipsamis (fuller's teasel) 

7fi. Macrosiphum rosae (Linn.) 

77. Macrosiplnim rudbeckiae (Fitch) 

104. HJiopalosiplium persicae (Sulz.) 
Di^porum (fairy bell) 

79. Macrosiphum salanifolii (Ashmead) 
Dock, see Sumex 
Dogwood, see Cornws 
Douglas fir, see Pseudotsuga 
Dracaena (dragon tree) 

ill. Aphis avenae Fabr. 
Dragon tree, see Dracaena 
Elderberry, see Samhucus 
Elm, see Vlmus 
Elymus (wild rye) 

68. Macrosiphum granarium (Kirby) 
English ivy, see Eedera 
Epilohium (fireweed) 

1.36. Ajyhis oenothcrae Oestlund 
Eriobotrya (loquat) 

139. Aphis pomi de Geer 
Erodium. (alfilerilla) 

79. Macrosiphum solanifolii (Ashmead) 

104. Shopalosiphum persicae (Sulz.) 
Erysimum (western wallflower) 

1.55. Siphocoryne capreae (Fabr.) 
Escallonia (escallonia) 

104. Phopalosiphum persicae (Sulz.) 
Eschscholt^ia (California poppy) 

123. Aphis gossypii Glover 
Everlasting, see Gnaph-alium 
Fagiis (beech) 

2. PhyllapMs fagi (Linn.) 
Fairybell, see Dipsorum 
Fennel, see Foeniculum 
Fenugreek, see Trigonella 
Fern, asparagus, see Asparagus 
Fern, Boston, see Nephrolepis 
Fern, holly, see Cyrtomium 
Fig marigold, see Mesevibryanthemum 
Figwort, see Scrophularia 
Fir, see Abies 

Fir, Douglas, .see Pseudotsuga 
Fireweed, see Epilobium 
Foeniculum (fennel) 

155. Siphocoryne capreae (Fabr.) 



166 MISCELLANEOUS STUDIES 

Foxglove, see Digitalis 

Foxtail, see Alopec^lrus ' 

Fragaria (strawberry) 

90. Myzus fragaefolii Cockerell 

Fraxinus (ash) 

171. Prociphilus venafuscus Patch 

167. Thecahius californicus (Davidson) 

Fuller 's teasel, see Dipsacus 

Fuchsia (fuchsia) 

79. Macrosiphum solanifoUi (Ashmead) 
88. Myzus circumflexus (Buckton) 

Gambleweed, see Sanicula 

Geranium, see Pelargonium 

Geranium (cranesbill) 

104. Bhopalosiphuin persicae (Sulz.) 
German ivy, see Senccio 

Gladiohis (gladiolus) 

88. Myzus circumflexus (Buckton) 
Glycyrrhisa (liquorice) 

131. Aphis medicaginis Koch 
Gyiaplialium (everlasting) 

146. Aphis senccio Swain 
60. Macrosiphum amlirosiae (Thomas) 
Gooseberry, see Eiics 
Goosefoot, see Chenopodium 
Gossypium (cotton) 

123. Aphis gossypii Glover 
Gourd, see Cucurbita 
Goutweed, see Aegopodium 
Graminaceae (various species) 

111. Aphis avenae Fabr. 

67. Macrosiphum dirhodum (Walker) 

68. Macrosiphum granarium (Kirby) 

105. Ehopalosiphum rhois Monell 
Grape, see Vitis 

Grindelia (marsh grindelia) 

146. Aphis senecio Swain 
Hawthorn, see Crataegus 
Hazelnut, see Corylus 
Hcdera (English ivy) 

109. Aphis angelic^ae Koch 

124. Aphis hederae Kalt 

104. Ehopalosiphum persicae (Sulz.) 
Hedge mustard, see Sisymbrium 
Hedge nettle, see Staehys 
Eelianthus (sunflower) 

123. Aphis gossypii Glover 

132. Aphis middletonii Thomas 
146. Aphis senccio Swain 

60. Macrosiphum amirosiae (Thomas) 
77. Macrosiphum riidheckiae (Fitch) 
104. Ehopalosiphum persicae (Suli.) 



A SYNOPSIS OF THE APHIDIDAE 167 

Hemlock, Poison, see Conium 
Hemlock, Water, see Cicuta 
Heracleum (cow parsnip) 

123. Aphis goss!/i}ii Glover 

125. Aphis heraclei Cowen 
Heteromeles (California holly, Christmas berry) 

170. Frociphilus alnifoli-ae (Williams) 

103. Ehopalosiphum nervatum Gillette 
Heuchcra (alum root) 

69. Macrosiphum heuclicrae (Thomas) 
Hibiscits (rose mallow) 

121. Aphis euonomi Fabr. 
Holly fern, see Cyrtonium 
Hollyhock, see Althaea 
Holly, mountain, see Heteromeles 
Honey flower, see Melianthus 
Honeysuckle, see Lonicera 
Hop, see Humulus 
Hordeum (barley) 

111. Aphis avei)ae Fabr. 
68. Macrosiphum granarium (Kirby) 
Houndstongue, see Cynoglossiim 
Humulus (hop) 

123. Aphis gossypii Glover 
98. Phorodon humuli (Schrank) 
Hydrangea (hydrangea) 

123. Aphis gossypii Glover 
Indian mallow, see Abut don 
Ironweed, see Veronina 
Ivy, Engislh, see Hedera 
Ivy, German, see Senecio 
Jasminum (jessamine) 

70. Macrosiphum jasmini (Clarke) 
Jessamine, see Jas-ininnm 

Jimpson weed, see Datura 
Juglans (walnut) 

24. Callipterus calif amicus (Essig) 

25. Callipterus caryae Monell 

23. Chromaphis juglandieola (Kalt.) 

26. Monellia caryella (Fitch) 
Knotweed, see Polygonum 
Lactuca (lettuce) 

79. Macrosiphum solanifolii (Ashmead) 
Lamb 's-quarters, see Chenopodium 
Lathyrus (sweet pea) 

74. Macrosiphum iii-si (Kalt.) 
Laurel, see Laurus 
Laurel, California, see Umiellularia 
Laurestinus, see Viburnum 
Laurus (laurel) 

150. Aphis vibumicolens n.sp. 



168 MISCELLANEOUS STUDIES 

Lavatera (tree mallow) 

104. Ehopalosiplmm persicae (Sulz.) 
Leatlier root, see Psorales 
Lemon, see Citrus 
Lepidium (peppergrass) 

123. Aphis gossypii Glover 
Lettuce, see Lactuca 
Ligusticum (lovage) 

155. Siiihocoryne caprcae (Fabr.) 
Lilac, see Syringa 
Lilac, Mountain, see Ceanotlius 
Lilium (lily) 

123. Aphis gossypii Glover 
88. Myzus circumflexus (Buckton) 
Lily, see Lilium 
Lily, Water, see Nymphaea 
Linden, see Tilia 
Liquorice, see Glycyrrliira 
Liriudendron (tulip tree) 

104. Ehopalosiphum persicae (Sulz.) 
Lithospermum 

127. Aphis lithospenni Wilson 
Loco weed, see Astragalus 
Locust, see Soiiiiia 
Loganberrj-, see Huhus 
Lonicera (honeysuckle) 

157. Siphocoryne pastinacae (Linn.) 
Loquat, see Eriobotrya 
Lovage, see Ligusticum 
Lupinus (lupine) 

59. Macrosiphum albifrons Essig 
Lycopersicum (tomato) 

91. My:us li/copf-rsicae (Clarke) 

104. Bhopalnsiphum persicae (Sulz.) 
Madia (tarweed) 

77a. Macrosiphum rudhecMae (Fitch) var. madia n.var. 
Madron, see Arbutus 
Mallow, Indian, see Aiutilon 
Mallow, Eose, see Hibiscus 
Mallow tree, see Lavatera 
Malva (cheeseweed) 

121. Aphis euonotni Fabr. 

123. Aphis gossypii Glover 

104. Ehopalosiphum persicae (Sulz.) 
Manzanita, see Arctostaphylos 
Maple, see Acer 
Marigold, see Calendula 
Marigold, fig, see Mesembriianthrmum 
Matthiola (ten-weeks' stock) 

141. Aphis pscudobrassicae Davis 
Mayten, see Maytetius 
Maytenus (mayten) 

121. Aphis euonomi Fabr. 



A SYNOPSIS OF THE APHIDIDAE 169 

Medicago (alfalfa, bur clover, etc.) 

131. Aphis viedicaginis Koch 
74. Macrosiplium pisi (Kalt.) 
Meliantlius (honey flower) 

104. Bhopalosiplmm persicae (Sulz.) 
Melilotus (sweet clover) 

131. Aphis medicaginis Koch 
Mesembryanthemum (fig marigold) 

121. Aphis euonomi Fabr. 
Milk thistle, see Silyhum 
Milkweed, see Asclepias 
Morning glory, see Convolvulus 
Morus (mulberry) 

133. Aphis mori Clarke 
Mountain holly, see Heteromeles 
Mountain lilac, see Ceanothus 
Mugivort, California, see Ai-temisia 
Mulberry, see Morus 
Musa (banana) 

111. Aphis avcnac Fabr. 
Muskmelon, see Cucumis 
Mustard, see Brassica 
Mustard, Hedge, see Sisymhrium 
Mustard, Teasel, see Erysimum 
Nasturtium, see Tropaeolum 
Nectarine, see Prunus 
Nephrolcpis (Boston fern) 

58. Idioptcrus nephrelepidis Davis 
Nerium (oleander) 

13.5. Aphis nerii Fonsc. 
Nettle, Hedge, see Stachys 
Nettle, Stinging, see Urtica 
Nightshade, see Solamim 
Ninebark, see Physocarpus 
Nymphaea (water lily) 

123. Aphis gossypii Glover 

156. Siphocoryne nympliaeae (Linn.) 
Oak, see Quercus 
Oak, Poison, see Bhus 
Oak, Tanbark, see Pasania 
Oats, see Avena 
Oenothera (evening primrose) 

13(i. Aphis oenothcrae Oestlund 
Oldnian, see Artemisia 
Oleander, see Nerium 
Orange, see Citrus 
Orache, see Atriplex 
Orchidaceae (orchids) 

162. Cerataphis lataniae (Boisd.) 
Orthoearpus (owl clover) 

73. Macrosiphum orthocarpi Davidson 
Owl clover, see Orthoearpus 



170 MISCELLANEOUS STUDIES 

Oxalis (oxalis) 

97. Macros! phum solanifolii (Ashmead) 
104. EhopaJosiiihum pcrsicae (Sulz.) 

152. Toxoptera aurantii (Fonsc.) 
Pansy, see Viola 

Papaver (poppy) 

121. Aphis euonomi Fabr. {papaveris Fabr.f) 
Parsley, see Petroselinum 
Parsnip, see Pastinaca 
Parsnip, Cow, see Hcracleum 
Fasania (tanbark oak) 

20. Mi/^ocallis pasaniae Davidson 
Pastinaca (parsnip) 

156. Siphocoryne pastinacae (Linn.) 
Pea, see Pisum 
Pea, Cow, see Vigna 
Pea, Sweet, see Luthyrus 
Pea tree, see Caragona 
Peach, see Pruiius 
Pear, see Pyrus 
Pelargonium (geranium) 

97. Pcntalonia nigronervosa Coiiiiellct 

104. Hhopalosiplmm pcrsicae (Sulz.) 
Pentstemon (pentstemon) 

88. Myzus cireumflexus (Buckton) 

104. Ithopalosiphum pcrsicae (Sulz.) 
Pepper, see Ctipxicum 
Peppergrass, see Lepidium 
Periwinkle, see Vinca 
Persea (avacado) 

123. Aphis gossypii Glover 
Petroselinum (parsley) 

155. Siphocoryne capreac (Fabr.) 
Phalaris (canary grass) 

111. Aphis avenac Fabr. 

153. Hyalopterus arundinis (Fabr.) 
Pliascolus (bean) 

121. Aphis euonomi Fabr. (rumicis Linn.f) 
131. Aphis medicaginis Koch 
74. Macrosiphum pisi (Kalt.) 
Phragmites (reed grass) 

153. Hyalopterus anindinis (Fabr.) 
Phyllostachys (bamboo) 

12. My::ocaUis arundicolciis (Clarke) 
Physocarpus (ninebark) 

100. Ehopalosiplium coryliniim Davidson 
Picea (spruce) 

46. Lachnus glehnus Essig 
55. Lachnus vanduzei n.sp. 
158. Myzaphis aiietina (Walker) 
Pigweed, see Amaranthus, and Chenopodium 
Pimento, see Capsicum 



A SYNOPSIS OF THE APRIDIDAE 171 

Pimpinella 

155. Siphocorync capreac (Fabr.) 
Pine, see Pinus 

Pinus (pine) 

178. Chermcs cooleyi Gillette 

179. Chermes pinicorticis Fitch 
43. Essigella calif ornica (Essig) 
45. Laclmus ferrisi Swain 

48. Laclmus oregonensis Wilson 

49. Lachinis pini-radiatac Davidson 

50. Lachnus ponderosa Williams 
52. Lachnus sabinianus n.sp. 

53a. Lachnus tomcntusa (De Geer) (Addenda) 
176. Mindants abietinus Koch 
Pisttm (pea) 

74. Macrosiphum pisi (Kalt.) 
Pittosporum (pittosporum) 

139. Aphis pomi De Geer 

79. MacroMphum solanifolii (Ashmead) 
104. Slwpulosiphum pcrsicae (Sulz.) 
Plantago (plantain) 

123. Aphis gossjipii Glover 
129. Aphis malifoliae Fitch (?) 
88. Myzus circnmflerns (Buekton) 
Plantain, see Plantago 
Plantain, Water, sec Alisma 
Platanus (western sycamore) 

4. Drepanosiphum platanoides (Sehrank) 
Plum, see Prunus 
Polygonum (knotweed) 

100. Shopalosiphum liippopliacs (Koch). 

156. Siphocoryne nymphaeae (Linn.) 
Pomegranate, see Punica 

Pondweed, see Potamogeton 

Poplar, see Populus 

Poppy, see Papavcr 

Poppy, California, see Esclischolt-ia 

Populns (poplar, eottonwood) 

28. Arctaphis populifolii (Essig) 
■ 164. Pemphigus betae Doane 

165. Pemjihigus populi-caulis Fitch 

166. Pemphigus populi-transrersus Eiley 
181. Phylloxerina pop^^laria (Pergande) 

40. Ptcrocomma populifoliae (Fitch) 

167. Thccabius californicus (Davidson) 

168. Thecabius populiconduplifolixis (Cowen) 

169. Thecabius populi-monilis (Eiley) 

34. Thomasia populicola (Thomas) 

35. Thomasia salicola (Essig) 
Potamogeton (pondweed) 

156. Siphocoryne nymphaeae (Linn.) 
Potato, see Solanim 



172 MISCELLANEOUS STUDIES 

Primrose, Evening, see Oenothera 
Primula (cowslip) 

5(5. Amplioropliora latysiphon Davidson 
Prune, see Prunus 
Pruntis (almond, apricot, cherry, nectarine, peach, plum, prune) 

107. Aphis alamedensis Clarke 

114. Aphis cardui Linn. 

117. Aphis cerasifoliae Fitch 

138. Aphis persicae-niger Smith 
140. Aphis prunorum Dobr. 

153. Ei/alopterus ar^lndinis (Fabr. 

87. Myzus cerasi (Fabr.) 

98. Phorodon humuli (Schrauk) 
104. Shopalosiphum persicae (Sulz.) 
156. Siphocoryne nymphaeae (Linn.) 
Pseudotsuga (Douglas fir) 

178. Chermes cooleyi Gillette 

43. Essigella calif ornica (Essig) 

51. Lachnus pseudotsuga Wilson 

53. Lachnus taxifolia Swain 
171. Prociphilus venafuscus Patch 
Psorales (leather root) 

74. Macrosiphum pisi (Kalt.) 
Pteris (brake) 

75. Macrosiphum pteridis Wilson 
Punica (pomegranate) 

123. Aphis gossypii Glover 
Pumpkin, see Cucurtita 
Pyrus (apple, pear) 

123. Aphis gossypii Glover 

129. Aphis malifoliae Fitch 

139. Aphis pomi De Geer 

175. Eriosoma languinosa Hartig (pyricola B. & D.) 
174. Eriosoma lanigcrum (Hausraan) 
Qucrcus (oak) 

5. Drepanaphis accrifolii (Fitch) (?) 

14. Myzocallis ielliis (Walsh) 

15. Myzocallis castanicola Baker (davidsojii Swain) 

17. Myzocallis discolor (Monell) 

18. Myzocallis pmictatus (Monell) 

19. Myzocallis californicus Baker {maurcri Swain) 
21. Myzocallis querctis (Kalt.) 

3. Phyllaphis quercicola Baker 

36. Symydohius agrifoliae Essig 

37. Symydohius chrysolcpis Swain 
177. Vacuna dryophila Sehrank (?) 

Quince, see Cydonia 
Eadish, see Eaphanus 
Eagweed, see Amhrosia 
Eamona (black sage) 

142. Aphis ramona Swain 



A SYNOPSIS OF TEE APHIDIDAE 173 

Sanunculus (buttercup) 

132. Aphis middletonii Thomas 
104. Ehopalosiphum persicae (Sulz.) 

167. Thecabius calif ornicus (Davidson) 

168. Thecabius populiconduplifolius (Cowen) 
Baphanus (radish) 

112. Aphis brassicae Linn. 

141. Aphis pseudobrassicae Davis 

104. Ehopalosiphum persicae (Sulz.) 
Eeed, Giant, see Aruiido 
Keed grass, see Phragmites 
Bliamnus (buckthorn, coffeeberry) 

123. Aphis gossypii Glover 

92. Myeus rhamnus (Clarke) 
Rhus (poison oak) 

lO.o. Ehopalosiphum rhois Monell 
Bibes (currant, gooseberry) 

126. Aphis lioughtonensis Troop 
134. Aphis neo-mexicana Ckll. var. pacifica Dvdn. 
89. Myzus cynosbati (Oestlund) 

93. Mygus ribifolii Davidson 
Bobinia (locust) 

131. Aphis medicaginis Koch 
Eosa (rose, -wild and cultivated) 

67. Macrosiphum dirhodum (Walker) 

76. Macrosiphum rosae (Linn.) 
159. MyiiOphis rosarum (Walker) 

103. Mygus nervatum Gillette 
Rose, see Eosa 

Rose mallow, see Hibiscus 

Bubus (blackberry, loganberry, thimbleberry) 

143. Aphis rubiphila Patch 

57. Amphorophora rubi (Kalt.) 

95. Nectarosiphon rubicola (Oestlund) 
Bumex (dock, sorrell) 

121. Aphis euonomi Fabr. {rumicis Linn.) 

123. Aphis gossypii Glover 

146. Aphis seneeio Swain 

164. Pemphigus bctae Doane (?) 

104. Ehopalosiphum persicae (Sulz.) 
Rye, Wild, see Elymus 

Sagebrush, see Arteinisia 
Sage, Black, see Eamona 
Salix (willow) 

144. Aphis salicicola Thomas 
146. Aphis seneeio Swain 

29. Arctaphis viminalis (Monell) 
31. Fullau-aya saliciradicis Essig 

64. Macrosiphum californicum (Clarke) 

30. Micrella monella Essig 

182. Phylloxerina salicola (Pergande) 
40. Pterocomma flocculosa (Weed) 



174 MISCELLANEOVS STUDIES 

41. Ptcrocomma populifoUae (Fiteh) 

42. Pterocomma smithiae (Monell) 
155. Siphocoryne capreae (Fabr.) 

38. Slimy duhius macrostachyae Essig 

39. Symiidobius salicicorticis Essig 
32. Thomasia crucis Essig 

34. Thotnasia papulicola (Thomas) 

35. Thomasia salicola (Essig) 

44. Tuherolachnus viminaU,s (Fonsc.) 
Samhucus (elderberry) 

145. Aphis samhucifoliac Fiteh 

81. Macrosiphum stanleyi Wilsou 
104. Rhopalosiphum persicac (Sulz.) 
Sanicula (gambleweed) 

119. Ai^his cornifoliae Fitcli 
104. Ehnpalosiphum pcrsicae (Sulz.) 
Scrophularia (figwort) 

99. Pkorodon scrophulariae Thamos 
Senecio (German ivy, ivy seneeio) 
144. Apliis senecio Swain 

88. Myzus circumflexus (Buckton) 
104. Bhitpidosiphum persicae (Sulz.) 
Shepherd 's-pursc, sec Capsella 
Silyhum (milk thistle) 

121. Aphis euonomi Fabr. 
130. Aphis marutae Oestlund 
Sisymbrium (hedge mustard) 

88. Myzus eircumflexus (Bucktou) 
Smilax, see Asparagus 
Snowball, see Virburnum 
Snowberry, see Symphoricarpos 
Solanum (potato, nightshade) 

'iG. Amphorophora latysiphon Davidson 
79. Macrosiphum solanifolii (Ashmead) 
88. Myzus circumflexus (Buckton) 
102. Bhopalosiphum lactucae (Kalt.) 
104. Rhopalosiphum persicae (Sulz.) 
163. Trif'daphis radicicola (Essig) 
Sonchus (sow thistle) 

79. Macrosiphum solanifolii (Ashmead) 

80. Macrosiphum sonchella (Monell) 
102. Ehopalosiphum lactucae (Kalt.) 
104. Bhopalosiphum persicae (Sulz.) 

Sorghum 

129. Aphis maidis Fiteh 
Sorrell, see Eumex 
Sow thistle, see Sonchus 
Spinacia (spinach) 

123. Aphis gossyj'ii Glover 

104. Bhopalosiphum persicae (Sulz.) 
Spirea (spirea) 

148. Apliis spiraecola Patch 



A SYNOPSIS OF THE APHIDIDAE 175 

Spruce, see Picea 

Squash, see Cucurhita 
Stacliijs (hedge nettle) 

73. Macrosiphum ludoviciaiiae (Oestlund) 
88. Myzus circumfltxus (Buekton) 
Stock, Ten-week, see Matthiola 
Strawberry, see Fragaria 
Sti'awberry tree, see Arhutus 
Sugar beet, see Beta 
Sunflower, see Heliantlius 
Sweet clover, see Melilotus 
Sweet pea, see Lathyrus 
Sycamore, Western, see Platanns 
Symphoricarpos (snowberry) 

108. Aphis albipes Oestlund 
Syringa (lilae) 

131. Aphis medicaginis Koch 
Tacalote, see Centaurea 
Taraxacum (dandelion) 

82. Macrosiphum taraxici (Kalt.) 
Tarweed, see Madia and Hemitonia 
Teasel, Fuller 's, see Dipsacus 

Teasel, mustard, see Erysimum 
Thimbleberry, see iv«&«« 
Thistle, see Cirsium 
Thistle, Milk, see Silyhum 
Thistle, Sow, see Sonclnis 
Thuja (arbor vitae) 

.54. Lachnus tiijafiiinus (Del Guercio) 
Tilia (linden, basswood) 

10. Eucallipterus tiliae (Linn.) 
Tomato, see Lycopersicum 
Trifoliiim (clover) 

llfia. Aphis hal'eri Cowen 
131. Aphis medicaginis Koch 
Trigonella (fenugreek) 

69. Macrosiphum pisi (Kalt.) 
Triticum (wheat) 

111. Aphis avenae Fabr. 

64. Macrosiphum granarium (Kirby) 
Tropaeolum (nasturtium) 

121. Aphis euonomi Fabr. 

88. Myzus circumflcxus (Buekton) 
104. Ehopalosiphum persicae (Sulz.) 
Tule, California, see Typha 
Tulip, see Tulipa 
Tulip tree, see Liriodendron 
Tulipa (tulip) 

83. Macrosiphum tulipae (Monell) 
104. Shopalosiphum persicae (Sulz.) 

Turnip, see Brassica 



176 MISCELLANEOUS STUDIES 

Typha (California tule) 

111. Aphis avenac Fabr. 
153. Eyalopienis arundinis (Fabr.) 
68. Macrosiphum granarium (Kirby) 

156. Siphoeoryne nymphaeae (Linn.) 
Ulmus (elm) 

28. Aretaphis populifolii (Essig) (?) 

172. Colopha ulmicola (Fitch) 

173. Eriosoma americana (EUey) 

175. Eriosoma languinosa Hartig {pyricoJa B. & D.) 

174. Eriosoma lanigcrum (Hausman) 

79. Macrosiphum solanifolii (Ashmead) 
22. Myzocallis ulmifolii (Monell) 
Umiellularia (California laurel) 

88. Myzus circumflexus (Buckton) 
104. Ehopalosiphum. pcrsicae (Sulz.) 

157. Siphoeoryne pastinacae (Linn.) 
Urtica (stinging nettle) 

121. Apliis cuonomi Fabr. 
Valerian, Red, see Ccntranthus 
Valeriana 

84. Macrosiphum Valerianae (Clarke) 
Vernoiiia (ironweed) 

123. Aphis gossypii Glover 
Vetch, see Vicia 

Vihurnum (lauristinus, snowball) 
121. Aphis euonomi Fabr. 
139. Aphis pomi Dc Geer 
150. Aphis viburnicolens u.sp. 
Vicia (horse bean, vetch) 

121. Aphis euonomi Fabr. {fabae Scop.) 
131. Aphis medicaginis Koch 
74. Macrosiphum pisi (Kalt.) 
Vigna (blackeye bean, cowpea) 

131. Aphis medicaginis Koch 
Vineca (periwinkle) 

56. Amphorophora latysiphon Davidson 
88. Mysus cireumfiexus (Buckton) 
104. Ehopalosiphum pcrsieae (Sulz.) 
Viola (pansy, violet) 

58. Idiopterus nephrelepidis Davis 
74. Macrosiphum pisi (Kalt.) 
88. Myzus cireumfiexus (Buckton) 
106. Ehnpalosiphum vioUie Pergande 
Vitis (grape) 

180. Phylloxera vitifoliae (Fitch) 
Wallflower, iee Chciranthus 
"Wallflower, Western, see Erysimum 
Walnut, see Juglans 
Water hemlock, see Cicuta 
Watermelon, see CitruUus 
Water plantain, see Alisma 



A SYNOP^ila OF THE APHIDIDAE 177 

Wheat, see Triticu7n 
Willow, see Salix 
Yarrow, see Achillea 
Yucca (yucea) 

151. Ai'ltis yuccae Cowen 
Zantedeschia (calla) 

88. Myzus circumflexus (Buckton) 
Zea (corn) 

111. Aphis avenae Fabr. 

128. Aphis maidis Fitch 
Zizia 

155. Siphocoryne capreae (Fabr.) 



178 MISCELLANEOUS STUDIES 



ADDENDA 

Since the preparation of this manuscript there have appeared a few papers^i' 
in which there are some new records for certain of the California Aphididae 
and in which there are notes concerning the synonymy of some of the species. 
These records are noted here and are listed in the Host Plant Index (appendix 2). 

2. PhyUaphis fagi (Linn.) on Fagus tricolor, Oakland (Essig, p. 321). 

7. Euceraphis betulae (Koch) on Betula populifoHu laciniata and B. papy- 
rifera (Essig, pp. 322-323). 

10. EucaUipterus tiliae (Linn.) on TiUa tomcntosn, Berkeley (Essig, p. 323). 
Baker places this species in the genus MyzocalUs, for although it is quite distinct 
from the type of Mii^ocaUis. various species form definite connections leading to 
this one. 

15. MyzocalUs castanicola Baker (Baker, p. 424). This name has been sug- 
gested by Baker to replace M. castaneae (Buekton) (preoccupied by castaneae 
(Fitch)). Therefore the name suggested by the author, M. davidsoni Swain, 
must be dropped. E.ssig (p. 323) lists M. castaneae (Fitch), but he refers to this 
species. 

19. MyzocalUs caUforuicus Baker (Baker, pp. 421-422). This is the same 
species as described by the author under the name, MyzocalUs niaureri Swain, 
which name will have to be dropped, and replaced by M. ealifornicus Baker. 

53a. Lachnus tomentosus (De Geer), on Finns radiata, Berkeley (Gillette, 
pp. 140-141). This species is very similar to L. pini-radiatae Davidson, accord- 
ing to Gillette. The author finds on looking over his specimens that some of them 
labeled L. pini-radiatae Dvdn. are this species, particularly those taken on the 
campus at Berkeley. 

56. Amphorophora latysiphon Davidson, on Clirysantlunnim and Primula sp., 
Berkeley (Essig, p. 329). 

68. Macrosiphum granarium (Kirby), on Alopccurns pratensis, Ampdodesma 
tenax, and Elyinus sji., Martinez (Essig, p. 328). 

76. Macrosiphum rosae (Linn.) on Dipsaciis fulloiium and Ccntrantlms ruber, 
Berkeley (Essig, p. 329). 

79. Macrosiphum solanifolii (Ashmead), on Achillea millefolium and Pitto- 
sporum tubira, Berkeley, and on Ulmus americanu^, San Francisco (Essig, p. 329). 

88. Myzus circuraflexus (Buekton), on Lilium spp., Pentstemon spectabilis, 
and Umbelhdaria ealifornica. Berkeley (Essig, p. 335). 

102. Rhopalosiphum lactucae (Kalt.). Dobrovliansky lists this as a synonym 
of E. ribis (Buekton), giving the latter name preference. 



30 Baker, A. C, Eastern aphids, new and little known, II, Jour, Econ, Ent., 
vol. 10, pp. 421-433, 1917. 

Baker, A. C. The correct name for our apple-grain aphis. Science, vol. 46, 
pp. 410-411, 1917. 

Davidson, W. M., The reddish-brown plum aphis, Jour. Econ. Ent., vol. 10, 
pp. 330-353. 1917. 

Dobrovliansky, V. V., A list of aphids found on cultivated plants in the gov- 
ernment of Kharkov, in Pests of Agriculture, Kharkov, Bull, 1916; reviewed in 
Rev. Appl. Ent., vol. 5, pp. 561-562, 1917. 

Essig, E. O., Aphididae of California, Univ. Calif. Publ. Entom., vol. 1, pp. 
301-346, 1917. 

Gillette, C. P., Some Colorado species of the genus Luehniis. Ent. Soc, Am,, 
vol, 10, pp. 133-146, 1917. 

Van der Goot, P.. Zur Kenntnis der Blattliiuse Java's, in Contrib. a la fauna 
der Indes neerlandaises, vol. 1, pp. 1-301, 1916. 



A SYNOPSIS OF THE APEIDIDAE 179 

104. Rhopalosiphum persicae (Sulzer), on Bnccharis douglasii, CentraiUhus 
ruber, Clarkia ctiytin.s, Dipsdcus fullonum, Escallonia pulverulcnta, Rclianthus 
animus, Lavatcra assurgentiflora, Liriodendron Udipifera, Mtiianthus major, 
Pcntstcmon spcctabilis, Pittosporum spp., and Vmbcllularia califurnica, Berkeley 
(Essig, pp. 331-332). 

111. ApMs avenae Pabr. It would appear from a study of Baker's paper in 
Science tliat the common California species is Aphis prunifoliae Fitch. It is 
certain that it is distinct from A. cerasifoliae Fitcli, which has been taken here 
once and is described in this paper. If it is possible, as Baker says, that A. 
cerasifoliae Fitch is a synonym of A. padi Linn., then our common species must 
be known as A. prunifoliae Fitch. From the brief description of Aphis (Siphon- 
aphis) padi Linn, given by Van der Goot (pp. 71-72) it would appear that our 
species may be distinct, differing slightly in the comparative lengths of the 
cornicles and cauda. Consequently the author favors accepting the name. Aphis 
pimnifoliac Fitoh, for this species. 

123. Aphis gossypii Glover, on Asclepias speciosa, A. vestita, Lilium spcciosum 
rubrum, Lonicera sp., and Ehamnus purshiana, Berkeley and Oakland (Essig, 
pp. 338-339). 

131. Aphis medicaglnis Koch, on Citrxis sp., Sacramento, ami on Vigna sin- 
ensis, Moorjiark (Essig, p. 340). 

139. Aphis pomi De Geer, on Cotoneaster franchetii, Pittosporum eugenioides, 
and Viburnum tinus, Berkeley (Essig, p. 341). The author is inclined to believe 
this to be Aphis viburnicolens n.sp. (see no. 150) which is quite similar to Ajyhis 
pomi De Geer, but which is common on Fiburimm and related plants. He has not, 
however, seen Essig 's specimens, so can not state positively whether or not it is 
this species. 

140. Aphis prunoTum Dobr. Dobrovliansky places this species as a synonym 
of Siphocoryne nymphaeae (Linn.). This author noted the similarity of these 
two, but was not certain of their identity, so listed them as distinct species. 

141. Aphis pseudobrassicae Davis. Dobrovliansky believes this to be a syno- 
nym of Aphis erysinii Kalt. 

146. Aphis senecio Swain. Essig (p. 337) lists Aphis bal-eri Cowen from 
Trifolium pratense. This proves to be the true Aphis bal-eri Cowen and not 
A. senecio Swain, which is the species that has been hitherto called A. bal-eri 
Cowen In California. 

152. Toxoptera aurantii (Fonsc.) on Camellia japonica, Oakland (Essig, p. 
330). 

153. Hyalopterus arundinis (Fabr.). Both Dobrovliansky and Van der Goot 
list this as a synonym of B. pruni (Fabr.) giving the later preference. Accord- 
ing to Hunter, arundinis should have priority, but it is entirely possible that the 
dates he gives are incorrect. This point the author is unable to settle as he has 
not access to Fabrieius' works. 

156. Siphocoryne nymphaeae (Linn.). Davidson gives a brief account of the 
habits and biology of this species, as well as a description of the various forms. 

175. Eriosoma languinosa Hartig (pyricola Baker and Davidson). The 
species listed by Essig (p. 345) as Eriosoma sp. on Vlmus campestris in Berkeley 
and in Hayward is this species. 

115. Aphis cari Essig. Davidson recently remarked to the author that he 
could see no difference betiveen this species and Aphis heliantliii Monell. It is 
quite possible that these are synonyms. 



EXPLANATION OF PLATES 
PLATE 1 

Fig. 1. Myzocalli^ asclepwdis (Fitch), tarsus and claw. 

Fig. 2. Aphis senecio Swain, tarsus and claw. 

Pig. 3. Essigella calif ornica (Essig), sixth antennal segment and spur. 

Fig. 4. Aphis senecio Swain, sixth antennal segment and spur. 

Fig. 5. Essigella californica (Essig), eauda and anal plate (lateral view). 

Fig. 6. Aphis senecio Swain, eauda and anal plate (lateral view). 

Fig. 7. Eucallipterus tiliae (Linn.), eauda and anal plate. 

Fig. 8. Thomasia populicola (Thos.), eauda and anal plate. 

Fig. 9. Phyllaphis fagi (Linn.), third antennal segment. 

Fig. \0. Phyllaphis fagi (Linn.), sixth antennal segment. 

Fig. 11. Phyllaphis fagi (Linn.), eauad and anal plate. 

Fig. 12. Phyllaphis fagi (Linn.), front of head and antennal tubercles. 

Fig. 13. Phyllaphis coweni (Ckll.), Antenna. 

Fig. 14. Phyllaphis quercicola Baker, third antennal segment. 

Fig. 1.5. Phyllaphis quercicola Baker, fourth antennal segment. 

Fig. Iti. Phyllaphis quercicola Baker, fifth antennal segment. 

Fig. 17. Phyllaphis quercicola Baker, sixth antennal segment. 

Fig. 18. Phyllaphis quercicola Baker, forcwing. 

Fig. 19. Phyllaphis quercicola Baker, eauda and anal plate. 

Fig. 20. Phyllaphis querci, tarsal claw. 

Fig. 21. Drepanosiphum platanoides (Schr.), antennal tubercles. 



[180] 




( SWAIN ] PLATE 1 



PLATE 2 

Fig. 22. Mi/zocallis arundicoUns (Clarke), antennal tubercles. 

Fig. 23. Drcpaiuiphis acerifolii (Thomas), cornicle. 

Fig. 24. Drepanosiphum platanoides (Schr.), cornicle. 

Fig. 25. Moncllia caryella (Fitch), cornicle. 

Fig. 26. My^ocallis ielius (Walsh), cornicle. 

Fig. 27. Calaphis betulaccolrns (Fitch), antennal tubercles. 

Fig. 28. Calaphis bctulclla Walsh, antennal tubercles. 

Fig. 29. Euceraphis hetulae (Koch), antennal tubercles. 

Fig. 30. Ewalliptcrus tili-ae (Linn.), sixth antennal segment and spur. 

Fig. 31. Myzocaliis quercus (Kalt.), sixth antennal segment and spur. 

Fig. 32. Myzocaliis quercus (Kalt.), cornicle. 

Fig. 33. Eucallipterus tiliae (Linn.), cornicle. 

Fig. 34. Chromaphis juglandicola (Kalt.), sixth antennal segment and spur. 

Fig. 35. Chromaphis juglandicola (Kalt.), cornicle. 

Fig. 36. Drepanosiphum platanoides (Schr.), third antennal segment. 

Fig. 37. Drepanaphis acerifolii (Thomas), third antennal segment. 

Fig. 38. Calaphis betulae-colens (Fiteh), third antennal segment. 

Fig. 39. Euceraphis gillettei Dvdn., base of third antennal segment. 

Fig. 40. Euceraphis betulae (Koch), base of third antennal segment. 



[182] 




SWAIN 1 plate: 2 



PLATE 3 

Fig. 41. Eucallipterus flava (Dvdn.), base of third antennal segment. 

Fig. 42. Eucallipterus tiliac (Linn.), third antennal segment. 

Fig. 43. MyzocalUs coryli (Goetze), third antennal segment. 

Fig. 44. MyzocalUs coryli (Goetze), sixth antennal segment and spur. 

Fig. 45. MyzocalUs hellus (Walsh), sixth antennal segment and spur. 

Pig. 46. MyzocalUs iellus (Walsh), third antennal segment. 

Fig. 47. MyzocalUs alnifoliae (Fitch), third antennal segment. 

Fig. 48. MyzocalUs arundicolens (Clarke), third antennal segment. 

Fig. 49. Eucallipterus tiliac (Linn.), cornicle. 

Fig. 50. Eucallipterus tiliac (Linn.), anal plate. 

Fig. 51. MyzocalUs arundicolens (Clarke), cornicle. 

Fig. 52. MyzocalUs arundicolens (Clarke), anal plate. 

Fig. 53. MyzocalUs coryli (Goetze), cornicle. 

Fig. 54. MyzocalUs coryli (Goetze), anal plate. 

Fig. 55. MyzocalUs californicus Baker, third antennal segment. 

Fig. 56. MyzocalUs californicus Baker, sixth antennal segment and spur. 

Fig. 57. MyzocalUs pasaniae Dvdn., third antennal segment. 

Fig. 58. MyzocalUs quercus (Kalt.), third antennal segment. 

Fig. 59. MyzocalUs ulmifoUi (MoneU), third antennal segment. 

Fig. 60. MyzocalUs castanicola Baker, third antennal segment. 

Fig. 61. MyzocalUs castanicola Baker, eauda and anal plate. 

Fig. 62. MyzocalUs castanicola Baker, cornicle. 

Fig. 63. Calliptcrus californicus (Essig), sixth antennal segment ami spur. 

Fig. 64. CalUpterus californicus (Essig), third antennal segment. 

Fig. 65. CalUpterus caryae Monell, third antennal segment. 



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43 




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[ SWAIN ] PLATE 3 



PLATE 4 

Fig. 66. Callipterus caryae Monell, sixth antennal segment and spur. 

Fig. 67. Monellia carycUa (Fitch), sixth antennal segment and spur. 

Fig. 68. Monellia caryella (Fitch), third antennal segment. 

Fig. 69. Arctaphis populifolii (Essig), eauda. 

Fig. 70. Micrella monclla Essig, cauda. 

Fig. 71. Arctaphis populifolii (Essig), third antennal segment. 

Fig. 72. Micrella vionella Essig, third antennal segment. 

Fig. 73. Syviydobius macrostachyae Essig, third antennal segment. 

Fig. 74. Symydobi)ts salicicorticis Essig, third antennal segment. 

Fig. 75. Fullawaya saliciradicis Essig, third antennal segment. 

Fig. 76. TlwinaMa crucis Essig, third antennal segment. 

Fig. 77. Thomasia populicola (Thomas), third antennal segment. 

Fig. 78. Thomasia salicicola (Essig), third antennal segment. 

Fig. 79. Lachnus ferrisi Swain, tarsal claw. 

Fig. 80. Pterocomma popiilifoliae (Fitch), tarsal claw. 

Fig. 81. Pterocomma floeculosa (Weed), cornicle. 

Fig. 82. Pterocomma populifoliae (Fitch), cornicle. 

Fig. 83. Essigella californica (Essig), antenna. 

Fig. 84. Longistigma sp., front wing. 



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77 




: SWAIN ] PLATE 4 



PLATE 5 

Fig. 85. Lacknii^ sp., front wing. 

Fig. 8G. Tuberolachims viminalis (Fonsc), hind tarsus. 

Fig. 87. Eulachnus rileyi Davis, hind tarsus. 

Fig. 88. Lachnus vanduzei n.sp., third antennal segment. 

Fig. 89. Laclinus ferrisi Swain, first, second, and third antennal segments. 

Fig. 90. Laohnus ferrisi Swain, fourth, fifth, and sixth antennal segments. 

Fig. 91. Laclinus ferrisi Swain, cornicle. 

Fig. 92. Lachnus pseudotsugae Wilson, tip of front wing. 

Fig. 93. Lachnus tujafiUnus (Del Guereio), tip of front wing. 

Fig. 94. Lachnus occidentalis Dvdn., third antennal segment. 

Fig. 95. Laclinus pini-radiatae Dvdn. (?), third antennal segment. 

Fig. 9(i. Lachnus glchnus Essig, third antennal segment. 

Fig. 97. Lachnus glelinus Essig, cornicle. 

Fig. 98. Lachnus pseudotsugae Wilson, third antennal segment. 

Fig. 99. Lachnus taxifolia Swain, hind tarsus. 

Fig. 100. Lachnus taxifolia Swain, fourth, fifth and sixth antennal segments. 

Fig. 101. Lachnus taxifolia Swain, first, second, and third antennal segments. 



[188] 












SWAIN I PLATE 5 



Fig. 


102. 


Fig. 


103. 


Fig. 


104. 


Fig. 


105. 


Fig. 


106. 


Fig. 


107. 


Fig. 


108. 


Fig. 


109. 


Fig. 


110. 


Fig. 


111. 


Fig. 


112. 


Fig. 


113. 


Fig. 


114. 


Fig. 


115. 


Fig. 


116. 



PLATE 6 

Laclinus taxi folia Swain, wing. 

Liiclmus taxifoUa Swain, cornicle of apterous female. 

Lachnus pondcrosa Williams, third antennal segment. 

Laclinus tujafillnus (Del Guercio), third antennal segment. 

Macrosiplmm rosae (Linn.), antennal tubercles. 

Nectaro-siphon rubicola (Oest.), antennal tubercles. 

Rhopalosiphum persicae (Sulz.), antennal tubercles. 

N ectarosiphon rubicola (Oest.), cornicle. 

Idiopterus ncplirclepidis Davis, wing. 

Amphorophora rubi (Kalt. ), antennal tubercles. 

Myzus cerasi (Fabr.), antennal tubercles, 

Amphorophora ruhi (Kalt.), cornicle. 

Toxoptera aurantii (Fonsc), cornicle. 

Phorodon humuli (Sehr.), antennal tubercles of alate females. 

Phorodon humnli (Schr.), antennal tubercles of apterous females. 



|l!m| 




[SWAIN ] PLATE 6 



PLATE 7 

Fig. 117. Phorodon humuli Schr., cornicle. 

Fig. 118. Phorodon humuli Schr., eauda. 

Pig. 119. Ehopalosiphum persicae (Sulz.), cornicle. 

Pig. 120. lihopalosiphum peswae (Sulz.), cauda. 

Pig. 121. Miizus cerasi (Fabr.), cornicle. 

Pig. 122. Myzus cerasi (Fabr.), cauda. 

Fig. 123. N ectarosiphon rubicola (Oest.), cauda. 

Pig. 124. N ectarosiphon morrisoni Swain, antennal tubercles. 

Fig. 125. Nectarosiplion morrisoni Swain, third antennal segment. 

Fig. 126. N ectarosiphon morrisoni Swain, cauda. 

Pig. 127. N ectarosiphon morrisoni Swain, cornicle. 

Pig. 128. Macrosiphiim stanlcyi Wilson, cornicle. 

Fig. 129. Macrosiphum solanifolii (Ashm.) (from Snnchus), cornicle. 

Fig. 130. Macrosiphum pi^i (Kalt.), cornicle. 

Fig. 131. Macrosiphum calif ornicum (Clarke), third antennal segment. 

Fig. 132. Macrosiphum calif ornicum (Clarke), cornicle. 

Fig. 133. Macrosiphmn cucurbitae (Thomas), third antennal segment. 

Pig. 134. Macrosiphum cucurbitae (Thomas), cornicle. 

Pig. 13.5. Macrosiphum granarium (Kirby), third antennal segment. 

Pig. 136. Macrosiphum ludovicianae (Oest.), third antennal segment. 

Fig. 137. Macrosiphum solanifolii (Ashm.), cornicle. 

Fig. 138. Macrosiphum solanifolii (Ashm.), third antennal segment. 



[192] 




[ SWAIN 1 PLATE 7 



PLATE 8 

Fig. 139. Macrosiplium solanifolii (Ashm.) (from Citrns), cornicle. 

Fig. 140. Macrosiplium solanifolii (Ashm.) (from Citrus), third antennal 
segment. 

Fig. 141. Macrosiphum sanboryii Gillette, cornicle of apterous female. 

Fig. 142. Macrosiphum artemisiae (Fonsc), cornicle. 

Fig. 143. Macrosiphum albifrons Essig, third antennal segment. 

Fig. 144. Macrosiphum albifrons Essig, cornicle. 

Fig. 145. Macrosiplium artemisiae (Fonsc), third antennal segment. 

Fig. 146. Macrosiphum artemisicola (Williams), third antenal segment. 

Fig. 147. Macrosiphum artemisicola (Williams), cornicle. 

Fig. 148. Macrosiphum granarium (Kirby), cornicle. 

Fig. 149. Macrosiphum ludovicianae (Oest.), cornicle. 

Fig. 150. Macrosiphum pisi (Kalt.), third antennal segment. 

Fig. 151. Macrosiphum rosae (Linn.), third antennal segment. 

Fig. 152. Macrosiphum rosae (Linn.), cornicle. 

Fig. 153. Macrosiphum rudbechi-ae (Fitch), cornicle. 

Fig. 154. Macrosiphum rudheclciae (Fitch), third antennal segment. 

Fig. 155. Macrosiphum sanborni Gillette, cauda apterous female. 

Fig. 156. Macrosiphum dirhodum (Walker), cornicle. 

Fig. 157. Macrosiplium dirhodum (Walker), third antennal segment. 

Fig. 158. Macrosiphum stanleyi Wilson, third antennal segment. 

Fig. 159. Macrosiphum solanifolii (Ashm.) (from Souclius), third antennal 
segment. 

Fig. 160. Macrosiphum solanifolii (Ashm.) (from Sonchti-s), cauda. 



I 194] 




[SWAIN ] PLATE 8 



Fig. 161. 

Fig. 162. 

Fig. 163. 

Fig. 164. 

Fig. 165. 

Fig. 166. 

Fig. 167. 

Fig. 168. 

Fig. 169. 
segment. 

Fig. 170. 

Fig. 171. 
ment. 

Fig. 172. 

Fig. 173. 

Fig. 174. 

Fig. 175. 

Fig. 176. 

Fig. 177. 

Fig. 178. 

Fig. 179. 

Fig. 180. 

Fig. 181. 

Fig. 182. 

Fig. 183. 

Fig. 184. 

Fig. 185. 
ments. 

Fig. 186. 



PLATE 9 

Amplwrophora latysiphon Dvdn., cornicle. 

Amphoropliora rubi (Kalt.), cauda. 

Toxoptera aurantii (Fonsc), third antennal segment. 

Ehopalosiphum violae Pergande, wing. 

Bhopalosiphum hippophaes Koch, cornicle. 

Shopalosiphum nervatum Gillette (from Arbutus), wing. 

Shopalosiphum corijUnum Dvdn., third antennal segment. 

Bhopalosiphum persicae (Sulz.), third antennal segment. 

Jthopdlosiphum nervatum Gillette (from Arhutus), third antennal 

Bhopalosiphum hippophaes Koch, third antennal segment. 
Bhopalosiphum nervatum GUlette (from rose), third antennal seg- 

Siphocori/ne niimphaeae (Linn.), third antennal segment. 

Bhopalosiphum rhois Monell, third antennal segment. 

Bhopalosiphum violae Pergande, third antennal segment. 

Myzus circumflexus (Buckton), third antennal segment. 

Mysus braggii Gillette, third antennal segment. 

Myzus fragaefolii Ckll., third antennal segment. 

Myzus rhamni (Fonsc), third antennal segment. 

Myzus cerasi (Fabr.), third antennal segment. 

Myzus ribis (LLnn.), third antennal segment. 

Hyalopterus arundinis (Fabr.), cornicle. 

Aphis cuonomi Fabr., cornicle. 

Siphocoryne caprcae (Fabr.), cornicle. 

Liosomaphis berberidis (Kalt.), conricle. 

Hyalopterus arundinis (Fabr.), third and fourth antennal seg- 

Hyalopterus arundinis (Fabr.), cauda. 



[196] 




-J^^T T^T^.o.o ° ° l^r^"^^ " "3^ 



SWAIN 1 PLATE 9 



PLATE 10 

Fig. 187. Aphis euonomi Fabr., wing. 

Fig. 188. Aphis salicicola Thomas, wing. 

Fig. 189. Aphis medicaginis Koch, third and fourth antennal segments. 

Fig. 190. Aphis euonomi Fabr. (?), third and fourth antennal segments. 

Fig. 191. Aphis avenue Fabr., wing. 

Fig. 192. Aphis gossijpii Glover, cornicle. 

Fig. 193. Aphis gossypii Glover, cauda. 

Fig. 194. Aphis samhucif oliae Fitch, cauda. 

Fig. 195. Aphis samhucif oliae Fitch, cornicle. 

Fig. 196. Myzaphis abietina (Walker), third and fourth antennal segments. 

Fig. 197. Myzaphis abietina (Walker), cornicle. 

Fig. 198. Aphis albipes Oest., eoniiele. 

Fig. 199. Aphis albipes Oest., cauda. 

Fig. 200. Aphis albipes Oest., third and fourth antennal segments. 

Fig. 201. Aphis avenae Fabr., cornicle. 

Fig. 202. Aphis avenae Fabr., third and fourth antennal segments. 

Fig. 203. Aphis brassicae Linn., cornicle. 

Fig. 204. Aphis brassicae Linn., third and fourth antennal segments. 

Fig. 205. Aphis euonomi Fabr., cornicle. 

Fig. 206. Aphis euonomi Fabr., cornicle. 

Fig. 207. AiJhis euonomi Fabr., third and fourth antennal segments. 

Fig. 208. Aphis cardui Linn., third and fourth antennal segments. 

Fig. 209. Aphis cardui Linn., cornicle. 

Fig. 210. Aphis ceanolhi Clarke, cornicle. 

Fig. 211. Aphis ceanothi Clarke, third and fourth antennal segments. 

Fig. 212. Aphis cookii Essig, third and fourth antennal segments. 

Fig. 213. Aphis cookii Essig, cauda and anal plate. 

Fig. 214. Aphis cookii Essig, cornicle. 

Fig. 215. Aphis gossypii Glover, third and fourth antennal segments. 

Fig. 216. Aphis maidis Fitch, cauda. 

Fig. 217. Aphis maidis Fitch, antenna. 

Fig. 218. Aphis maidis Fitch, cornicle. 

Fig. 219. Aphis middletonii Thomas, cornicle. 

Fig. 220. Aphis middletonii Thomas, third and fourth antennal segments. 

Fig. 221. Aphis nerii Ponsc, cornicle. 

Fig. 222. Aphis nerii Fonsc, third and fourth antennal segments. 

Fig. 2231 Aphis persicae-niger Smith, cornicle. 

Fig. 224. Aphis persicae-niger Smith, third and fourth antennal segments. 



[198] 




cz^ 







I SWAIN 1 PLATE 10 



PLATE 11 



Fig. 225. 

Fig. 226. 

Fig. 227. 

Fig. 228. 

Fig. 229. 

Fig. 230. 

Fig. 231. 

Fig. 232. 

Fig. 233. 

Fig. 234. 

Fig. 235. 

Fig. 236. 

Fig. 237. 

Fig. 238. 

Fig. 239. 

Fig. 240. 

Fig. 241. 

Fig. 242. 

Fig. 243. 

Fig. 244. 

Fig. 245. 

Fig. 24G. 

Fig. 247. 

Fig. 248. 

Fig. 250. 

Fig. 251. 

Fig. 252. 
ments. 

Fig. 253. 

Fig. 254. 
and spur. 

Fig. 255. 
females. 

Fig. 256. Siphocoryne caprcae (Fabr.), cauda and supra-caudal spine of 
apterous females. 

Fig. 257. Siphocoryne pa.^tinacae (Linn.), tliird and fourth antenna! seg- 
ments. 

Fig. 258. Siphocoryne pastinacae (Linn.), fifth and sixth antennal segments 
and spur. 

Fig. 259. Siphocoryne pastinacae (Linn.), eauda of apterous female. 

Fig. 260. Siphocoryne pastinacae (Linn.), cauda of alate female. 

Fig. 261. Siphocoryne pastinacae (Linn.), cornicle. 



Aphis pomi De Geer, cauda. 

Aphis pomi De Geer, antennae. 

Aphis pomi De Geer, cornicle. 

Aphis prunorum Dobr., cauda. 

Aphis prunorum Dobr., third and fourth autenual segments. 

Aphis prunorum Dobr., cornicle. 

Aphis pscudobrassicae Davis, tliird and fourth antennal segments. 

Aphis ramona Swain, antenna. 

Aphis ramona Swain, front of head. 

Aphis ramona Swain, cauda and anal plate. 

Aphis ramona Swain, cornicle. 

Aphis cuonomi Fabr., cornicle. 

Aphis cuonomi Fabr., third and fourth antennal segments. 

Aphis salicicola Thomas, cornicle. 

Apliis salicicolii Tliomas, third and fourth antennal segments. 

Apliis samhucifoliae Fitch, third and fourth antennal segments. 

Aphis senecio Swain, cauda. 

Aphis senecio Swain, cornicle. 

Aphis senecio Swain, front of head. 

Aphis senecio Swain, third and fourth antennal segments. 

Aphis senecio Swain, fifth, sixth antennal segments, and spur. 

Aphis setarae Thomas, cornicle. 

Aphis setarae Thomas, third and fourth autenual segments. 

Aphis malifoliae Fitch, cornicle. 

Apliis malifoliae Fitch, fourth antennal segment. 

Liosomaphis licrheridis (Kalt.), front of head. 

Liosomaphis bei-beridis (Kalt.), third and fourth autenual seg- 

Siphocoryne capreae (Fabr.), third and fourth antennal segments. 
Siphocoryne capreae (Fabr.), fifth and sixth antennal segments 

Siphocoryne capreae (Fabr.), cauda and supra-caudal spine of alate 



[200] 




; SWAIN ) PLATE 1 1 



PLATE 12 

Fig. 262. Myeocallis discolor (Monell), fore wmg. 

Fig. 263. Myzoeallis discolor (Monell), third antennal segment. 

Fig. 264. Myzoeallis bellus (Walsh), fore wing. 

Fig. 265. Myzoeallis bellus (Walsh), third antennal segment. 

Fig. 266. Myzoeallis ealifornicus BaTcer (maureri Swain), fore wing. 

Fig. 267. Myzoeallis castanicola Baker (davidsoni Swain), fore wing. 

Fig. 268. Myzoeallis arandinariae Essig, third antennal segment. 



[202] 






2 tr 
[SWAIN J PLATE 12 



PLATE 13 

Pig. 269. Siimydobius chrysolepis Swain, head. 

Fig. 270. Symydobius ohrysolepis Swain, cornicle. 

Fig. 271. Symydobius chrysolepis Swain, anal plate. 

Fig. 272. Symydobiibs chrysolepis Swain, antenna. 

Fig. 273. Symydobius chrysolepis Swain, fore wing. 

Fig. 274. Symydobius chrysolepis Swain, hind ^vLng. 

Fig. 275. Thomasia popuUcola (Thomas), fore wing. 



[204] 






275 



[ SWAIN ] PLATE 13 



PLATE 14 

Fig. 276. Toxoptera auratitii (Fonsc), fore wing. 

Fig. 277. SJiopalosiphum lactucae (Kalt) head. 

Fig. 278. Ehopalosiphum lactucae (Kalt.), third antennal segment, aptera. 

Fig. 279. Ehopalosiphum lactucae (Kalt.), third antennal segment, alate. 

Fig. 280. Ehopalosiphum lactucae (Kalt.), fourth and fifth antennal seg- 
ments, alat€. 

Fig. 281. Ehopalosiphum lactucae (Kalt.), sixth antennal segment, alate. 

Fig. 282. Ehopalosiphum lactucae (Kalt.), cornicle, alate. 

Fig. 283. Ehopalosiphum lactucae (Kalt.), eauda, alate. 

Fig. 284. Ehopalosiphum lactucae (Kalt.), cornicle, aptera. 

Fig. 284o. Ehopalosiphum lactucae (Kalt.), Cauda, aptera. 



[206] 




2 5^43 



[ SWAIN 1 PLATE 14 



PLATE 15 

Fig. 285. Aphis viburnicolens n.sp., third antennal segment. 

Fig. 286. Aphis viiurni-colens n.sp., cornicle. 

Fig. 287. Aphis viburnicolens n.sp., Cauda. 

Fig. 288. Aphis cerasifoliae (Fitch), head. 

Fig. 289. Aphis cerasifoliae (Fitch), fifth and sixth antennal segments. 

Fig. 290. Aphis cerasifoliae (Fitch), third and fourth antennal segments. 

Fig. 291. Aphis cerasifoliae (Fitch), end of wing. 

Fig. 292. Aphis cerasifoliae (Fitch), side of abdomen showing Cauda, cor- 
nicle, and lateral tubercles on segments one, two, three, four, and seven. 



[208] 




Z'iK 



iZ9 





2S-7 




[ SWAIN ] PLATE 15 



PLATE 16 

Fig. 293. Aphis viarutae Oest., head. 

Fig. 294. Aphis marutae Oest., third and fourth antennal segments. 

Fig. 295. Aphis marutae Oest., fifth and sixth antennal segments. 

Fig. 296. Aphis vmrutae Oest., antenna, aptera. 

Fig. 297. Aphis marutae Oest., end of abdomen, aptera. 

Fig. 298. Aphis marutae Oest., cauda, alate. 

Fig. 299. Aphis marutae Oest., cornicle, alate. 

Fig. 300. Aphis neomexicana Ckll., var. pacifica Dvdn., tliird and fourth 
antennal segments. 

Fig. 301. Aphis neomexicana Ckll. var. pacifica Dvdn., cornicle. 

Fig. 302. Aphis neomexicana CkU. var. pacifica Dvdn., cauda. 

Fig. 303. Aphis yuccac Cowen, fourth, fifth, and sixth antennal segments. 

Fig. 304. Aphis yuccae Cowen, third antennal segment. 

Pig. 305. Aphis yiu'cae Cowen, tip of abdomen. 



[210] 




dis 



X94 



Z96 




300 





S99 



i;9r 




30; 




50Z 



504 




[ SWAIN 1 PLATE 16 



PLATE 17 

Fig. 306. Myzus ribis (Linn.), head. 

Fig. 307. Myzus cerasi (Fabr.), head. 

Fig. 308. Myzaphis rosarum (Walker), head, alate. 

Fig. 309. Myzaphis rosarum (Walker), third and fourth antenual segments. 

Fig. 310. Myzaphis rosarum (Walker), fifth and sixth antennal segments. 

Fig. 311. Myzaphis rosarum (Walker), tip of wing. 

Fig. 312. Myzaphus rosarum (Walker), end of abdomen. 

Fig. 313. Myzaphis rosarum (Walker), head, aptera. 

Fig. 314. Myzaphis rosai-um (Walker), antenna, aptera. 

Fig. 315. Myzaphis rosarum (Walker), cornicle, aptera. 

Fig. 316. Myzaphis rosarum (Walker), cauda, aptera. 

Fig. 317. Myzaphis rosarum (Walker), hind tarsus, aptera. 



[212] 





307 



309 





31 3 




3(7 




SWAIN I PLATE 17 



A SYNOPSIS OF THE APEIDIDAE 



215 



INDEX TO GENERA AND SPECIES 



abietes, hachnus, 47. 
abietina, Myzaphis (Aphis), 134. 
abietinus, Mindarus, 1.50. 
aeei'ifolii, Drepanaphis (Siplwno- 

phora, Macrosiphum), 18. 
acliyrantcs, Sliopalosiplium, 80. 
agrifoliae, Symydobius, 38. 
alameilensis, Aphis, 93. 
albifrons, Macrosiphum, 60. 
albipes. Aphis, 93. 
obit, Myzocaliis, 21. 
ahiifoliae, CaUipterus, 20. 
almfoliae Lachnus. 20. 
alnifoliae Myzocallis, 22. 
aInifoUae Prociphilus (Pemphigus), 

146. 
ambrosiae, Macrosiphum (Siphono- 

phora), 60. 
americana, Eriosoma (Schizoneura), 

148. 
Amphorophora, 54. 

cicutae, 54. 

latysiphon, 54, 178. 

rubi, 54. 

rubicola, 77. 
angelicae, Aphis, 93. 
anuulata, Callipterinella (Chaitopho- 

rus), 31. 
Aphis, 88. 

abietina, 134. 

alamedensis, 93. 

albipes, 93. 

angelicae, 93. 

artemisiae, 61. 

arundinis, 130. 

atriplicis, 93. 

aurantii, 129. 

avenae, 94, 179. 

bakeri, 123, 124. 

bakeri, 6, 179. 

bellus, 24. 

berberidis, 130. 

betulaecolens, 18. 

brassieae, 95. 

calendulicola, 96. 

capreae, 132. 

cardui, 96. 

cari, 96, 179. 

caryella, 30. 

ceanothi, 96. 

ceanothi-hirsut i, 96. 

cerasi, 73. 

cerasifoliae, 97.. 

citri, 105. 

cooki, 100. 

cornifoliae, 100. 

coryli, 25. 

crataegifoliae, 100. 



dirhodum, 63. 
dryophila, 150. 
euonomi, 101. 
fabae, 102, 104. 
fagi, 13. 
frigidae, 105. 
gossyini, 100. 
g'ossypii, 105, 179. 
g^ranarium, 64. 
hederae, 106. 
heraclei, 107. 
houghtonensis, 107. 
humuli, 79. 
juglandis, 28. 
lactucac, 82. 
languinosa, 149. 
lanigervm, 149. 
lithospermi, 108. 
lutescens, 117. 
maidis, 94. 
maidis, 108. 
man. 120. 
malifoliae, 108. 
marutae, 112. 
medicaginis, 114, 179. 
middletonii, 115. 
mori, 116. 
neomexicaua, 116. 
nerii, 117. 
nymphaeae, 133. 
oenotherae, 118. 
oregonensis, 119. 
padi, 94. 

papaveris, 102, 104. 
pastin-acae, 133. 
pcrsicae, 85. 
persicae-niger, 119. 
pisi, 66. 
platanoides, 17. 
pomi, 120, 179. 
pomi, 109. 
populifoliae, 41. 
pruni, 96. 

prunorum, 121, 179. 
prunifoliae, 130, 179. 
pseudobrassicae, 122, 179. 
quercus, 27. 
ramona, 122. 
rhamni, 76. 
rosae, 67. 
rosarum, 134. 
rubi, 54. 
rubiphila, 122. 
rudbeckiae, 67. 
rufomaculata, 137. 
rMmicis. 101, 106. 
salicicola, 123. 
sambucifoliae, 123. 
senecio, 123, 179. 
setariae, 124. 



216 



MISCELLANEOUS STUDIES 



sorbi, 108. 

spiraecola, 124. 

spiraeeHa, 125, 126. 

taraxici, 71. 

tetrapteralis, 125. 

tilMC, 21. 

viburnicolens, 126, 179. 

viminalis, 45. 

yuccae, 45. 

yuccicola, 128. 
aquilegiae, Myzus, 73. 
arbuti, Hhopalosiphum, 84. 
Arctaphis, 33. 

populifolii, 33. 

viminalis, 34. 
artomisicola, Macrosiphum {Siphono- 

phora), 61. 
artemisiae, Macrosiphum (Aphis), 61. 
arundicolens, Eucallipterus (Myzocal- 

lis), 24. 
arundicolens, Myzocallis (Callipterus) , 

22 
arundinariae, Myzocallis, 24. 
arundinis, Hvalopterus (Aphis), 130, 

179. 
atriplicis. Aphis, 93. 
aurantiae. Toxoptera. 129. 
aurantii, Toxoptera (Aphis), 129, 179. 
avouae. Aphis (Nectaropliora, Sipho- 
corj/nc), 94, 179. 



baccharadis, Macrosiphum (Nectaro- 

phora), 61. 
bak-eri. Aphis, 123. 
bakeri. Aphis, 6, 179. 
balsamifenie. Pemphigus, 142. 
bellus, Myzocallis (Aphis, Callip- 

tems), 24. 
berberidis, Liosomaphis (Aphis, Uho- 

palosipbum), 130. 
betae. Pemphigus, 142. 
betulae, Cliaitophorus, 31. 
betulae, Euceraphis (Callipterus) , 19, 

178. 
betulaecolens, Calaphis (Aphis, Cal- 

liptcrtis), 18. 
braggii, Myzus, 73. 
brassicae. Aphis, 95. 
Byrsocrypta, 148. 
ulmicola, 148. 

C 
calendulicola. Aphis, 96. 
Calaphis, 18. 

betulaecolens, 18. 
rastancae, 24. 
ealifornica, Essigella (L(ichnus), 44. 
californicum, Maerosipliuni (Nectaro- 

phora), 62. 
californicus, Callipterus (Monellia), 

29. 
californicus Myzocallis, 178. 
californicus Theeabius (Pemphigus), 
144. 



Callipterinella, 31. 

annulata, 31. 
Callipterus, 28. 

alnifoliae, 20. 

arundicolens, 22. 

beUus, 24. 

betulae, 19. 

betulaecolens, 18. 

californicus, 29. 

earyae, 29. 

caryella, 30. 

castaneae, 24. 

coryli, 25. 

discolor, 25. 

hyalinus, 26. 

juglandicola, 28. 

juglandis, 28. 

punctatus, 26. 

quercus, 27. 

tiliae, 21. 

ulmifolii, 27. 

viminalis, 34. 
eapreae, Siphocoryne (Aphis), 132. 
cardui. Aphis, 96. 
oarduinum, Phorodon, 73. 
cari. Aphis, 96, 179. 
earyae, Callipterus (Monellia), 29. 
caryella, Monellia (>4p/ws, Callip- 
terus), 30. 
castaneae, Calaphis (Callipterus), 24. 
castaneae, Myzoc-aJlis, 178. 
castanicola, Myzocallis, 178. 
ceanothi. Aphis, 96. 
ceanothi-hirsuti. Aphis, 96. 
cerasi, Myzus (^pJii^), 73. 
cerasifoliae, Aphis, 97. 
Cerataphis, 140. 

lataniae, 140. 
Cerosipha, 137. 

cupressi, 137. 
Chaitophorus, 33. 

annulata, 31. 

betulae, 31. 

negundinis, 36. 

nigrac, 37. 

populicola, 36. 

populifoliae, 33. 

salicioola, 37. 

smithiae, 34. 

■!!tffli(wi(is, 34. 
Chermes, 151. 

cooleyi, 151. 

coweni, 151. 

pinicorticis, 152. 
Chromaphis, 28. 

juglandicola, 28. 
chrysanthemi, Macrosiphum (Siphono- 

phora), 62. 
chrysanthemi, Macrosiphum, 69. 
chrysolepis, Symydobius, 38. 
cicutae. Ampliorophora, 54. 
eircumflexus, Myzus (Siphonophora). 
citri. Aphis, 105. 



A SYNOPSIS OF THE APHIDIDAE 



217 



citrifoUi, Macrosipltum {Ncctaro- 

phora), 69. 
Cladobius, 41. 

rufulus, 41. 

salicti, 43. 
Coccus. 140. 

latanioc, 140. 

pinicorticis, 152. 
Colopha, 148. 

ulmicola, 148. 
Coloratloa, 137. 

rufoniaculata, 137. 
conii, Siplwcoriinc, 133. 
cooki, Aphis, 100. 
cooleyi, Clierme.>i, 151. 
cornifoliae, Aphis, 100. 
coryU, Myzocallis {Aphis, Callip- 

terus), 25. 
corylinum, Rhopalosiphum, 81. 
cowciii, Chcrmes. 151. 
coweui, Phyllaphis (Pemphigus), 13. 
crataegfifolii. Aphis, 100. 
p.rucis, Thoiiiasia, 36. 
Cryptusiphum, 13. 

tahoense, 13. 
cucurbitae, Macrosiphum (Siphono- 

phora), 62. 
cupressi, Cerosipha, 137. 
cynosbati, Myziis (Ncctarophora), 75. 

D 

davidsoni, Myzocallis, 24, 178. 
detitatn-s, Lachiius, 45. 
destructor, Macrosiphum, 66. 
dianth', Rhopalosiphum, 85. 
dirhodum, Macrosiphum {Aphis), 63. 
discolor, Myzocallis {Cnllipterus), 25. 
Drepanaphis, 18. 

acerifolii, 18. 
Drepanosiphum, 17. 

acerifolii, 18. 

platanoides, 17. 
dryophila, Vacuna (Aphis, Cliaito- 
phorus), 150. 

E 
Eichoclmitophorus, 33. 

populifolii, 33. 
Eriosoina, 148. 

americaua, 148. 

languinosa, 149, 179. 

lanigerum, 149. 

pyricola, 149. 
Essigella, 44. 

ealifornica, 44. 
essigi, Myzocallis, 27. 
Eucallipterus, 20. 

arundicolens, 24. 

flava, 20. 

tiliae, 21, 178. 
Euceraphis, 19. 

betulae, 19, 178. 

flava. 2u. 

gillettei, 20. 
euonomi, Aphis, 101. 



fagi, Phyllaphis, 13, 178. 

ferrisi, Laclinus, 47. 

flava, Eucallipterus (Euceraphis), 20. 

flocculosa, Pterocomma (Melanoxan- 
thus), 40. 

foeniculi, Siphocoryne, 132. 

fragaefolii, Myzus, 75. 

fraxiihi-dipetalae, Prociphilus (Pem- 
phigus), 146. 

frigidae. Aphis, 105. 

frigidae, Macrosiphum, 61. 

FuUawaya, 35. 
salieiradicis, 35. 

G 

galeopsidis, Phorodon, 81. 
gillettei, Euceraphis, 20. 
glehnus, Lachnus, 47. 
godetiae, Myms, 85. 
gossypii. Aphis, 100. 
gossypii. Aphis, 105, 179. 
granarium, Macrosiphum (Aphis), 64, 
178. 

H 
hederae, Aphis, 106. 
heraclei. Aphis, 107. 
lieuclierae, Macrosiphum (Siphono- 

phura), 64. 
hippophoaes, Rhopalosiphum, 81. 
houghtouensis. Aphis, 107. 
howardi. 'Rhopalosiphum, 86. 
humuli, Phorodon (Aphis), 79. 
Hyadaphis, 132. 

pastinacoe, 132. 

umhellulariae, 133. 
hyalinu^, Myzocallis (Callipterus), 26. 
Hyalopterus, 130. 

arundinis, 130, 179. 



Idiopterus, 56. 
nephrelcpidis, 56. 



jasmini, Macrosiphum (Ncctaro- 
phora), 64. 

juglandicola, Chromaphis (Lachnus, 
Callipterus), 28. 

juglandis, Callipterus (Aphis), 28. 

juiiiperi, Lachnus, 50. 

L 

Lachmclla, 50. 

tujafiliiius, 50. 
Laclinus, 45. 

ahicii.'i. 47. 

alnifoliae, 20, 22. 

californicus, 44. 

dental'!^, 45. 

ferrisi, 47. 

glehnus, 47. 

juglan-dicola, 28. 

junipcri, 50. 



218 



MISCELLANEOUS STUDIES 



occidentalis, 47. 

oregonensis, 48. 

pini-radiatae, 48, 178. 

ponderosa, 48. 

pseudotsugae, 48. 

sabinianus, 49. 

taxifolia, 50. 

tomentosus, 178. 

tujafilinus, 50. 

vanduzei, 50. 

viiniiuilis, 45. 
lactucae, Macrosiphum {Nectaro- 
phora), 65. 

lactuea Rhopalosiphum (Aphis), 82. 
laevigatac, Macrosiphum, 62. 
langiiinosa, Eriosoma {Aphis), 149, 

179. 
langerum, Eriosoma (Aphis, Schizo- 

neura), 149. 
lataniae, Cerataphis (Coccus), 140. 
latysiphoii, Amphorophora, 54, 178. 
Liosomaphis, 130. 

berberidis, 130. 
lithospermi. Aphis, 108. . 
ludoTicianae, Macrosiplium (Sipho)io- 

phora), 65. 
lutcscens. Aphis, 117. 
lycopersici, Myzus (Ncctarophora), 
76. 

M 

Macrosiphum, 57. 
acerifolii, 18. 
albifroDS, 60. 
ambrosiae, 60. 
artemisiae, 61. 
artemisieola, 61. 
baccharadis, 61. 
californicum, 62. 
idirysanthemi, 62. 
chi-yaanthcmi, 69. 
citrifolii, 69. 
cucurbitae, 62. 
destructor, 66. 
dirhodum, 63. 
frigidac, 61. 
grauarium, 64, 178. 
heueherap, 64. 
jasmiui, 64. 
lactucae, 65. 
laevigatae, 62. 
ludovicianae, 65. 
orthoearpus, 66. 
pisi, 66. 
pteridis, 67. 
rosae, 67. 
rubicola, 77. 
rudbeckiae, 67. 
rudbeckiae var. madia, 68. 
sanborni, 69. 
sulanifolii, 69, 178. 
sonchclla, 70. 
snnchi, 60. 
stanleyi, 70. 



taraxici, 71. 
tulipae, 71. 
yalerianae, 71. 
macrostachyae, Symydobius, 38. 
madia, Macrosiphum (rudbeckiae), 68. 
maidis, Aphis, 84. 
maidis. Aphis, 108. 
mali. Aphis, 120. 
malifoliae, Aphis, 108. 
marutae, Aphis, 112. 
maureri, Myzocallis, 26, 178. 
medicaginis. Aphis, 114, 179. 
Melanoxantherium, 41. 
rufulum, 41. 
salicti, 43. 
Melanoxanthus, 40. 

ftocculosa, 40. 
Micrclla, 35. 

monella, 35. 
middletonii. Aphis, 115. 
Miiidarus, 150. 

abietinus, 150. 
monella, Micrella, 35. 
Moncllia, 29. 
californicii-s, 29. 
caryae. 29. 
caryclla, 30. 
mori. Aphis, 116. 
morriaoui, Neetarosiphon, 78. 
Myzaphis, 134. 
abietina, 134. 
rosarum, 134. 
Myzocallis, 21. 
'aliii. 21. 
ainifoliae, 22. 
arundicolens, 22. 
aruiidicolens, 24. 
arundinariae, 24. 
bellus, 24. 
californicus, 178. 
castaneae, 178. 
castanicola, 178. 
eoryli, 25. 
davidsoni, 24, 178. 
discolor, 25. 
cssigi, 27. 
hyalimis, 26. 
maureri, 26, 178. 
pasaniae, 26. 
punctatus, 26. 
quercus, 27. 
ulmifoUi, 27. 
woDdu'ortlii, 27. 
Myzus, 71. 
aquelegiae, 73. 
braggii, 73. 
cerasi, 73. 
circumflexus, 74. 
cynosbati, 75. 
f'ragaefolii, 75. 
godetiae, 85. 
lycopersici, 76. 
pcrsicae, 80, 85. 
rhamni, 76. 



A SYNOPSIS OF THE APHIDIDAE 



219 



ribes, 75. 
ribifolii, 76. 
rosarum, ] 34. 
varians, 77. 
vincae, 74. 



N 



Nectarophora 

avenae, 94. 

iacoharadis, 61. 

californicum, 62. 

citrifolii, 69. 

cynosbati, 75. 

jasmini, 64. 

ZactMcae, 65. 

lycopcrsici, 76. 

pwi, 66. 

rlmmni, 76. 

rosae. 67. 

so)icheJIa, 70. 

Valerianae, 71. 
Nectai'osiphon, 77. 

morrisoni. 78. 

rubicola, 77. 
neguntlinis, Thomasia (Chaitopliorits) , 

36. 
neomexieana, Aphis, 116. 
npphrelepirlis, Idiopterus, 56. 
uerii, Aphis, 117. 
nervatum, Ehopalosiphum, 84. 
niyrac, Chaitophorus, 37. 
nigronervoaa, Pentalonia, 78. 
nymphaeae, Siphocoryne {Aphis, Eho- 
palosiphum), 133, 179. 

O 

occidentalis, Lachnus, 47. 
ocnotherae, Aphis, 118. 
orcgonensis. Aphis, 119. 
oregoneusis, Laclmus, 48. 
orthocarpus, Macrosiphum, 66. 



padi, Aphis, 94. 

panicola, Schizoneura, 150. 

pasaniae, Myzoeallis, 26. 

pastinaeae, Siphocoryne {Aphis, Hy- 

adaphis), 133. 
pastinaeae, Hyadaphis, 132. 
Pemphigus, 141. 

aliiifoliac, 146. 

balsamiferae, 142. 

betae, 142. 

californieus, 144. 

coweni, 13. 

fraxini-dipetalae, 146. 

populicaiilis, 143. 

populiconduplif alius, 145. 

populimanilis, 145. 

populi-transversus, 143. 

populi-trausversus, 143. 

radieicola, 141. 

ranunculi, 144. 

vcnafuscus, 146. 



Pentalonia, 78. 

uigronervosa, 78. 
persieae, Rhopalosiphum {Aphis, 

Myzus), 179, 185. 
persicae-niger, Aphis, 119. 
Phoroclon, 79. 

earduinum, 73. 

galeopsidis, 81. 

humuli, 79. 

scrophulariae, 80. 
Phyllaphis, 12. 

coweni, 13. 

fagi, 13, 178. 

querci, 15. 

quercicola, 15. 
Phylloxera, 152. 

popularia, 153. 

.lalicola, 153. 

va-siatrix, 152. 

vitifoliae, 152. 
Phylloxerina, 153. 

jjopularia, 153. 

salicola, 153. 
pinicorticis? Chermes, 152. 
pini-radiatae, Lachnus, 48, 178. 
pisi, Macrosiphum {Aphis, Nectaro- 
phora), 66. 
platanoides, Drepanosiphum {Aphis), 

17. 
pomi. Aphis, 109. 
pomi, Aphis, 120, 179. 
ponderosa, Lachnus, 48. 
popularia, Phylloxerina {Phylloxera), 

293. 
populca, Pterocomma, 41. 
populicaulis. Pemphigus, 143. 
populieola, Thomasia {Chaitophorus), 

36. 
populiconduplifolius, Thecabius {Pem- 
phigus), 145. 
populifoliae, Chaitophorus, 33. 
populifoliae, Pterocomma {Ajthis), 41. 
populifolii, Aretaphis {Eichocluiito- 

jihorus), 33. 
populimonilis, Thecabius {Pc/nphi- 

gu^'), 145. 
populi-transversus. Pemphigus, 143. 
populi-transversus, Pemphigus, 143. 
Prociphilus, 146. 

aluifoliae, 146. 

fraxini-dipetalae, 146. 

vcuafuscus, 146. 
pruni. Aphis, 96. 
prunifoliac, Aphis, 130, 179. 
prunorum. Aphis, 121, 179. 
pseudobrassicae. Aphis, 122, 179. 
pseudotsugae, Lachnus, 48. 
pteridis, Macrosiphum, 67. 
Pterocomma, 40. 

flocculosa, 40. 

popuJea. 41. 

populifoliae, 41. 

smithiae, 43. 



MISCELLANEOUS STUDIES 



puuctatus, Mvzocallis (CaUqitents), 

26. 
pyricola, Eriosoma, 149. 

Q 

querci, Phyllaphis, 15. 
querci, Schizoneura, 15. 
quercicola, Phyllaphis, 15. 
quercus, M.vzocallis (Aphis, Callip- 
terus), 27. 

R 
radicicola, Trifidaphis (Pemphigus), 

141. 
rainona, Aphis, 122. 
r<inuncuH. Pemphigus, 144. 
rhamni. Aphis, 76. 
rhanini, Myzus (Nectarophora), 76. 
rhois, Rhopalosiphimi, 86. 
Rliopalosiphum, 80. 
arhi/rantis, 80. 
(trbuti. 84. 
berberidis, 130. 
eorylinum, 81. 
diaiithi. 85. 
liippophoaes, 81. 
h^ncardi, 86. 
lactucae, 82. 
ncrvatum, 84. 
niimpliaene, 133. 
persicae, 85, 179. 
rhois, 86. 
iuJipae, 85. 
violae, 86. 
riliifolii, Myzus, 76. 
ribes, Myzus, 75. 

rosae, Maerosiphum (Aphis, Nectaro- 
phora), 67. 
rosarum, Myzaphis (Aphis, Myzus), 

134. 
nibi, Amphorophora (Aphis), 54. 
rubicola, Nectarosiphura (Maero- 
siphum) (Ampliorophora), 77. 
rubiphila. Aphis, 122. 
riulbeekiae, Maerosiphum (Aphis), 67. 
rudbeckiae var. madia, Maerosiphum, 

68. 
rufomaculata, Coloradoa (Aphis), 137. 
rufulum, Melanoxanthcrium, 41. 
rufuht-s, Cladobius, 41. 
rumicis, Aphis, 101. 



sabinianus, Lachuus, 49. 

salieicola. Aphis, 123. 

salic.icola, Thomasia (Chaitophorus), 
37. 

salicieorticis, Symydobius, 39. 

saliciradicis, Fullawaya, 35. 

.mlicis, Siphocoryne, 132. 

salicola, Phylloxerina (Phylloxera), 
153. 

salicti, Cladobius (Melanoxan- 
thcrium), 43. 



sambucifoliae. Aphis, 123. 
sanborni, Maerosiphum, 69. 
Schizoneura, 148. 
amerieana, 148. 
lanigerum, 149. 
panicola, 150. 
qiierci, 15. 
serophulariae, Phorodon, 80. 
seneeio, Aphis, 123, 179. 
setariae. Aphis, 124, 
Siphocoryne, 131. 
avenae, 84. 
eapreae, 132. 
conii, 133. 
focnicidi, 132. 
nymphaeae, 133, 179. 
pastinacae, 133. , 

salicis, 132. 
xylostei, 133. 
Siphonophora, 60. 
acerifolii. 18. 
ambrosiae, 60. 
artnnisicola. 61. 
chrysaiitlu mi, 62. 
eirrumflcxus, 74. 
eururbitae, 62. 
hcuelierac, 64. 
ludovicianMe, 65. 
solanifoUi, 69. 
sonchrlla. 70. 
tuHpac, 71. 
smithiae, Pterocomma (Chaitoplwrus) , 

43. 
solanifolii, Maerosiphum (Siphono- 
phora), 69, 179. 
sonohella, Maerosiphum (Siphono- 
phora) (Nectarophora), 70. 
sonehi, Maerosiphum, 60. 
sorbi. Aphis, 108. 
spiraecola, Aphis, 124. 
spiraeelUi. Aphis, 125, 126. 
stauleyi, Maerosiphum, 70. 
Symydobius, 37. 
agrifoliae, 38. 
ehrysolepis, 38. 
inacrostaehyae, 38. 
salleicortieis, 39. 



tahoense, Cryptosiphum, 13. 
taraxici, Maerosiphum (Aphis), 71. 
taxifolia, Lachuus, 50. 
tetrapteralis. Aphis, 125. 
Thecabius, 144. 

californieus, 144. 

populiconduplifolius, 145. 

populimonilis, 145. 
Thomasia, 35. 

crucis, 36. 

negundinis, 36. 

populicola, 36. 

salieicola, 37. 

viminalis, 34. 



A SYNOPSIS OF THE APBIDIVAE 



221 



tiliae, Eueallipterus {Aphis, CalUp- 

term), 21, 178. 
tomeutosus, Lachnus, 178. 
Toxoptera, 129. 

aurantiae, 129. 

aurantii, 129, 179. 
Trifidaphis, 141. 

ratlieicola, 141. 
■Tuberolachnus, 45. 

viminalis, 4.5. 
tujafilinus, Lachnus {Lachneilla), 50. 
tulipae, Macrosiphura {Siphonophora) , 

71. 
tulipae, Hhopalosiphum, 85. 

U 
ulmieola, Colopha {Brysocrypta), 148. 
ulmifolii, Myzocallis (Callipterus), 27. 
umbeUulariae, Hyadaphis, 133. 

V 

Vacuna, 150. 

dryophila, 150. 
Valerianae, Macrosiphum {Nectaro- 
pliora), 71. 



vanduzei, Lachnns, 50. 
varians, Myzus, 77. 
vastatrix. Phylloxera, 152. 
venafuscus, Prociphilus (Pemphigus), 

146. 
virburnicolens, Aphis, 126, 179. 
viminalis, Arctaphis {Callipterus, Chai- 

tophorus, Thmnasia), 34. 
viminalis, Tuberolachnus {Lachnus) 

{Aphis), 45. 
vinoae, Myzus, 74. 
violae, Ehopalosiphum, 86. 
vitifoliae, Phylloxera, 152. 

W 

looodworthi, Myzocallis, 27. 

X 

xylostci. Siphocoryne, 133. 



yuccae. Aphis, 128. 
yuccicola. Aphis, 128. 



MUTATION IN MATTHIOLA 



BY 

HOWARD B. FROST 



[Universit)- o( California Publications in Agricultural Sciences, Vol. 2, No. 4, pp. 81-190] 



MUTATION IN MATTHIOLA 



BY 

HOWARD B. FROST 



CONTENTS 

PAGE 

Introduction 81 

Genetic, literature relating to Mattliiola S4 

Methods 85 

Experimental data 89 

The occurrence of apparent mutants 89 

Characteristics and heredity of mutant tj'pes 92 

1. The early type _ 92 

2. The smooth-leaved type 118 

3. The large-leaved type 125 

4. The crenate-leaved type 127 

5. The slender type 135 

6. The narrow-leaved type 141 

7. Miscellaneous aberrant types 143 

8. Some probabilities of random sampling 145 

General discussion 153 

Summary 159 

Literature cited _ 161 



INTRODUCTION 

It is hardly safe to use the term mutation without first defining it. 
In this paper it will be taken to mean a genotypic change, or a change 
in essential hereditary constitution, due neither to immediate cross 
fertilization nor to segregation in a heterozygous parent. No attempt 
will be made to restrict the term to any of the known or supposed 
types of such genotypic change ; a limitation of this kind, which 
restricts the generally accepted sense of a widely used term, seems to 
tend to confusion rather than to clearness. 



rail 



224 MISCELLANEOUS STUDIES 

If we use the term factor mutation,'^ (Babeock, 1918) where the 
cytological change occurs within a locus, transforming a factor into a 
different factor, two analogous terms will apply where the cytological 
change is external to the locus. When the cytological change consists 
of a loss, reduplication, or transposition of one or more loci it may 
be called a Jocus inufaiion, and when the change consists in such 
phenomena affecting a whole chromosome it may be called a chromo- 
some mutation. If the term mnlaiion i.s applied to the cytological 
change itself, the last two types of mutation may be grouped together 
as extralocus mutations, while the first type consists of intraloeus 
mutations. Examples of factor mutation are white eye in Drosophila. 
and probably the rubrinervis type in Ocnotliera; an example of locus 
mutation is (possibly) "deficiency" in Drosophila: and examples of 
chromosome mutation are Oenothera gigas and 0. lata. 

It is now evident that the immediate problem with Oenothera relates 
to the mechanism of heredity in the genus. There are two sharply 
opposed views. One is that recently emphasized by Atkinson (1917, 
p. 254), when he says, "The evidence from Oenothera cultures points 
more and more to the conclusion of Shull that 'a hereditary mechanism 
must exist in Oenothera fundamentally different from that which dis- 
tributes the Mendelian unit-characters.' " The opposing view is 
represented by Muller's (1918) strictly Mendelian explanation for 
Oenothera, based on "an Oenothera-Vike ca.se in Drosophila" ; he says. 
"The striking parallel between the above behavior and that exhibited 
in Oenothera makes it practically certain that this, too, is a complicated 
case of balanced lethal factors." 

A notable feature of the extensive genetic study of Ornothrra is 
the lack of progress toward any definitely supported explanation of 
its hereditary mechanism which is not Mendelian. The only definite 
non-Mendelian hypothesis of chromosome behavior so far proposed, 
aside from "merogony" and other hypotheses (Goldschmidt, 1916) 
apparently possible but not proved for Oenothera, which as,sume loss 
of chromatin after fertilization, seems to be Swingle's (1911) 
"zygotaxis, " proposed for the apparently parallel case of Citrus. 
This .suggestion that F^ hybrids may differ, apart from non-uniformity 
of the Pj gametes, because of the establishment of permanently differ- 
ent arrangements of the chromosomes in the fertilized egg, still seems 
to be purely speculative. 

"With more or less "Oenothera-like" cases in other genera, the only 
definite progress in analysis seems to have resulted from the assump- 



■ MuUer (1918) has recently used point mutation in the same sense. 

[82] 



MVTATIOS IN MATTHJOLA 223 

tion of Mendelian segregation. AYith Oenothera itself, the trend of 
the evidence tends to favor this form of explanation. 

This fact is strikingly illustrated by two papers of de Vries (1918. 
1919) which have appeared since the present paper was written, 
especially as MuUer's (1918) complete report on the beaded- wing 
case in Drosophila (see especially pp. -471-474, 4S9, and 498-499) 
indicates that de Vries had hardly yet realized the full possibilities of 
the balanced- factor hypothesis. In the light of Muller's masterly 
demonstration of these possibilities, we may be confident that "mass 
mutation"' is merely ordinary segregation, and that the "unisexual" 
crosses of Oenothera are really "Mendelian" in their essential phe- 
nomena. Some difference of usage respecting the inclusiveness of 
the term Mendelian may be involved here, it is true, since apparently 
de Vries would apply it only to cases where strictly homologous factors 
are opposed in homologous chromosomes. Since, however (^Muller, 
1918), there are good reasons for expecting the occurrence of grada- 
tions of similarity and of synaptic attraction between opposed loci, and 
hence of gradations of linkage, the criterion of Mendelian behavior 
should obviou.sly be the occurrence of segregation between homologous 
chromosomes, whatever their degree of similarity or amount of cross- 
ing over. We have no reason to assume that an "unpaired" factor 
in a parent would so divide as to be included in all gametes; on the 
other hand, we have learned of a mechanism capable of insuring, in 
certain particular cases, the inclusion of a certain factor or group of 
factors either in every functional gamete or in every viable zygote. 

No doubt, as Davis (1917) says, "A great forward step will be 
taken in Oenothera genetics when types of proven purity have been 
established . . . ." Meanwhile, cases of "Oenothera-Uke" heredity in 
species known to possess the Mendelian mechanism deserve most 
thorough investigation. Special interest consequently attaches to the 
peculiar inheritance of certain apparent nnitations of the ten-weeks 
stock {Matthiola annua Sweet), a species in which various character- 
istics are typically Mendelian. A remarkable series of aberrant forms 
in this species'' has been briefly discussed in two preliminary com- 
munications (Frost, 1912 and 1916), and the present paper gives a 
fuller account of the same phenomena.* 



3 In the variety "Snowflake, " a glabrous, double-producing form with white 
flowers. 

•• While this paper was in ]iress Blakeslee and Avery (1910), have reported 
the occurrence of apparent mutations in Datura, which seem to be similar in 
almost every respect to those here discussed. 

IS3] 



226 MISCELLANEOUS STUDIES 

Apparent mutants were first found in the course of work on 
another problem, the relation of temperature to variation (Frost, 
1911), conducted at Cornell University. Studied incidentally at 
first, these new forms were later given special attention. About nine 
thousand plants, of which about two thousand were progeny of 
mutant -type parents of peculiar heredity (nearly one-fourth of the 
latter representing crosses with Snowtiake), have been examined 
altogether. Some of these plants have been grown at Riverside, where 
hybridization studies with mutant types are in progress. The present 
account considers the origin and characteristics of these types, their 
inheritance with self pollination, and the rather meager available data 
relating to their behavior in crossing. 

In connection with the work at Cornell, special acknowledgment 
is due to the late Professor John Craig, and to Dr. H. J. Webber 
and Dr. H. H. Love. Facilities for work were furnished by the depart- 
ments of Horticulture and Plant Breeding of the New York State 
College of Agriculture. 



GENETIC LITERATURE RELATING TO MATTHIOLA 

The work of Correns (1900) on Mattliiola furnislied one of the 
earliest confirmations of IMendel 's law, and also pointed to complica- 
tions not found by ilendel. The earlier literature, according to Correns, 
gives no indication of the study of Mattliiola hybrids beyond the first 
generation. 

In his later paper on aberrant hybrid ratios, the same author 
(1902) discusses complications in maize and in 3IattIiioIa. After 
referring the deviations foinid in maize to selective pollination, he 
considers a suggestion of de Vries relating to environmental modi- 
fication of Mendelian ratios, and him.self suggests the possibility of 
selective elimination of gametes. He says (pp. 171-172), "Solche 
Einfliisse brauchten nieht alle Sorten Keimzellen des Bastardes gleich- 
massig zti treffen, sondern sie kiinnten eine Sorte starker angreifen als 
die andere." 

Von Tsehermak (1904, 1912) has made extensive studies of 
Mattliiola hybrids, considering mainly, as did Correns, pubescence and 
flower color. The latter of these papers on hybrids in the genera 
Mattliiola, Pisinn, and Phaseolus represents a careful analytical test 
of the "factor hypothesis" of segregating inheritance, leading to the 
conclusion that the applicability of this hypothesis is strongly eon- 



[841 



MUTATION IN MATTHIOI.A 227 

firmed by the results secured. This work, with that of Miss Saunders, 
leaves no possibility of doubt that the typical Mendelian mechanism is 
present in Matthiola. 

The most extensive genetic work on Matthiola is evidently that of 
Miss Saunders, reported by herself (1911, 1911a, 1913, 1913a, 1915, 
1916) and by Bateson and Saunders, with others (1902, 1905, 1906, 
1908). This also is work on heredity in hybrids, with special emphasis 
on the factorial interpretation of the various complications relating 
to pubescence and to "doubleness" of flowers. 

Goldsehmidt (1913) has explained the inheritance of doubleness 
by sex linkage and lethal action of a femaleness factor in pollen 
formation, and his interpretation has been criticized by Miss Saunders 
(1913). I (Frost, 1915) have presented a somewhat different lethal- 
factor seheme. and Mi.ss Saunders (1916) has since restated her views 
and criticized mine. 

Muller (1917) has cited the inheritance of doubleness as a case of 
"balanced factors," in apparent agreement with my formulation. 

Apparently no one but the present writer (Frost. 1912, 1916; see 
also review by Bartlett, 1917) has reported experimental evidence of 
any notable tendency to apparent mutation in the genus, although 
de Vries (1906, p. 338) mentions the occasional occurrence of vigorous, 
rigidly upright individuals (a gigas type?), known at Erfurt as 
"generals," and refers to the rare mutative occurrence of single 
flowers on branches of double-flowering plants. Doubleness, and color 
variations in considerable number, have evidently arisen under culti- 
vation, probably through mutative changes. 



METHODS 

The general cultural methods employed for the first three genera- 
tions have been very briefly described elsewhere (Frost, 1911). 

The plants of the first four years were grown in pots in the green- 
house. The plants of the first generation came from one or both of 
two packets of commercial seed planted in the fall of 1906, and all 
plants in the later cultures (possibly excepting series 18) were 
descendants of these. The cultures will in general be designated by 
the year in which the seed was sown ; the field and greenhouse cultures 
of 1911 are indicated by 1911F and 1911 H respectively. 

Part of the seed planted, especially in 1908, came from unguarded 
flowers. The seed lots where thi.s occurred will be indicated in the 



(851 



228 MISCELLANEOUS STUDIES 

tabulation of parental data by italic figures, while protection possibly 
defective will be indicated by an asterisk. It is not probable that 
much vicinism occurred in the greenhouse cultiires. since this plant 
is well adapted to self fertilization. 

In the first year's (1906) cultures the plants in each experimental 
environment were separately numbered. Eaeli plant was designated 
bj- its number preceded b.y two letters indicative of the environment. 
For greenhouse temperature these letters were C (cool), M (medium 
temperature), and W (warm) ; for potting soiP they were S (sand), 
L (unfertilized "loam"), and G ("good" soil, fertilized). Thus CSl 
CS2, AVG9, etc.. were pedigree numbers of the first generation, and 
CG2-M8 and WG9-C10 of the second generation. A few syncotyle- 
donous plants outside the regular cultures of 1907 were called "WG9- 
synl. etc. 

For the work at Riverside a new system of numbering was adopted, 
better suited to ordinary pedigree cultures, and the numbers from 
this system are used below in the individual treatment of all but one 
of the mutant types ("early"). This is essentially Webber's (1906, 
p. 308) system, except that each initial or P, individual of a series is 
indicated by a letter; a full description has been published (Frost, 
1917). With 3Iattliiola each type or cross between two types that is 
tested receives a scries number, the apparent mutants themselves 
always being taken as the initial individuals of their selfed series. 

The cultures of 1908 included progeny of various parents, one being 
WG9-C10, an early and few-noded plant suspected of being a mutant. 

The cultures of 1910 consisted of a second-generation test of WG9- 
ClO, and a first-generation test of other possible mutants, with control 
lots. The plants were all grown on one bench in one greenhouse 
(house C). from thirty lots of fifteen seeds each, lots 1-17 relating to 
WG9-C10. The parents descended from WG9-C10 (see table 7) were 
selected as those with fewest internodes, a medium number of inter- 
nodes, and most" internodes in each house of the 1908 cultures, earli- 
ness of flo.wering being considered when parents were alike in number 
of internodes. The control parents were both few-noded and many- 
noded, relatively to their sibs. 

In 1911 eighty progenj^ lots were grown in the field at Ithaca. 
Lots 1 to 28, transplanted from the greenhouse, paralleled the test of 



•> Soil experimentally varied onlj- in the 1906 cultures, temperature varied in 
the two following years also. 

For house M, not the highest, which was e.xeeptioually high, but the next 
to the highest. 



[861 



MirAridX IX MATTIIIOI.A 229 

WG9-C10 made in lDlO-11 ; all available progeny of WG9-C10, except 
the crenate-leaved apparent mutant "WG9-C10-C10, were tested, with 
check lots between as before. Soil differences and unavoidable differ- 
ences between lots in time of transplanting combined with hot weather 
and drought to reduce the value of the results. The remaining fifty- 
two lots, all field-sown, included a further test of the heredity of 
aberrant types other than early. Most of these lots, however, were 
progeny of Snowtlake parents, grown to obtain evidence on the relation 
of temperature to nuitation and on the inheritance of doi;bleness of 
flowers, and therefore the results are not reported here. 

The 191 IH cultures eon.stituted a coldframe and greenhouse prog- 
eny test of mutant types, mainly in the second generation, the plants 
being grown in flats. 

There was added in 1912-13 a small greenhouse test bearing on the 
supposed mutative origin of WG9-C10, in view of the apparent possi- 
bility that WSl or WLIO, in the same house with the unbagged 'WGd, 
might have been heterozygous for the early type — cross pollination 
then giving the apparent mutant. 

Further progeny tests of the mutant types have been made in the 
field at Eiverside, beginning in the fall of 1913. Mainly on account 
of the unsuitability of the usually hot and dry climate of River- 
side, the cultures have been largely experimental and always on a 
small scale, and germination or development ha.s sometimes been un- 
satisf actor}'. Cultures have been started in October, November, 
January, and February, and a trial culture in progress at the time 
of writing was started in August. Some of the plants of the 1915-16 
cultures were kept until the summer of 1917, and many of them 
flowered for the first time when about a year old. 

In the cultures of 1913, growth was largely unsatisfactoi-y. and 
with part of the plants aphid injury interfered more or less with the 
classification of types. In the cultures of 1914, the seeds were largely 
lost through toxic effects favored by very shallow planting (as at 
Ithaca) and strong evaporation from the soil. In subsequent planting, 
the seeds, planted singlj- in small paper pots, were dropped into 
relatively deep holes punched in the soil, and covered with sand. 

The only field-grown plants closely resembling those grown in the 
greenhouse at Ithaca, it may be noted, have been those of the 1917 
cultures, grown in a lathhouse with added shade from muslin. 

In the cultures of 1915-16, with partial shade and more frequent 
irrigation than before, development was in general good; but even 



(871 



230 



MISCELLANEOUS STUDIES 



S 
a 



Eh 



S 



-^ s 





I 

G 

2 

o 

u 

c 

'i 
-1 

c 

> 

o 

E 

.s 

6 
S5 


C 
d 

3 

£ 

a 
a 

< 




5.47 ± .93« 
.96 ± 1.06 
.91 ± -.73 




c 

3 

z 


^ cc ^ ^ »o c^ ^ 






; ; h ; : : 




tUBUIB 

poB snoia 
-lunu saA-ea'j; 


::!—(:»—( ; 






: : f-H : f-H 


c 

1 


aapuais 


: f-i ": : ^H ^ 


adXi 
paABa(-MOJJB^ 


: :^ rt (N 


pad^> p9A-Bdi 
-8;Buajo-im3S 


: t— t ; : T-H 


9dX^ 
paABai-di«uaJO 


rf — irt : :0 -H ^ 


adXj 

paABdi-q;oomg 


M ': : (N ib -H -H 


3I 
-1 


iooo-*t^^ CO 

OOCOMi- t^ '1< 




None 

None 

None 

None 

None 

Selection in 

notebook" 

Selection at 

trans- 
planting 


s 

a 

1 








CG2 
WSl 
WLIO 
WG9 
All above 
All above 

CG2-F, 

and 
WG9-F, 



05 



CD 



o 
o 



o M ^ 



so ^ 
c - 






■ > 

S ^ 
> M 



y i2 ■ 

13 to •-! 



(U o 

a ~ 










5< =3 O rt ^j _c 






3 =S 
bo (V 



^ = j= £.a 






o o o 



c e 

<: H 






1881 



Mrr.lTlON IN MATrillOLA ■ 231 

here the mutant types, with one exception, often failed to grow satis- 
factorily or to set seed. Infection, probably by Fusarimn, evidently 
was the cause of the death of many of these plants in their second 
season. 

"With all cultures grown after (probably) those of 1906, special 
care was taken to secure random samples of seed, and after 1908 no 
plants were rejected. The only exception to this statement is the 
rejection of one pot out of every fifteen, by number and systematically, 
in the first twenty progeny lots of 1910. For the earlier cultures, a 
certain amount of selection must be recorded, as follows. In 1906 
the small and the largest plants were omitted at potting, and probably 
any weak and abnormal seedlings had been omitted at the preceding 
transplanting. In 1907 all markedly weak, late, or abnormal seedlings, 
as determined mainly by the appearance of the cotyledons, were 
omitted at the first transplanting; and the same was done in 1908, 
except that certain lots from old seed were unselected.' 

These last lots were arranged at transplanting in such a way that 
the weak and abnormal plants came at the end in each lot. 



EXPERIMENTAL DATA 
The Occurrence of Apparent Mutants 

In the cultures of 1906, 88 plants were grown to maturity, none 
of these being suspected of mutation. In the cultures of 1907, among 
170 plants one striking variant appeared; this plant, ^69-010, was 
exceptionally small and early in blooming. 

In the cultures of 1908, 714 plants were available, including ap- 
parent mutants in several hereditary lines as indicated in table 1. A 
striking feature of the results is the scarcity of apparent mutants 
among the seedlings classed as strictly normal at transplanting ; prob- 
ably the scarcitj- in the preceding years was due mainly to the rejection 
of abnormal seedlings (see "ilethods"). The first, second, and fourth 
of these forms have been common in later cultures, while the third 
and fifth have been rarer; the last three, if seen at all elsewhere, have 
not being recognized as belonging to the same types as these three 
plants. 



■ One tiny plant from WG9, probably not viable, was discarded. 



r89J 



232 



MJSCELLANEOrS STUDIES 



Table 2 shows the mimbers and percentages of apparent nmtants 
found in the enltures of 1910 and 1911F. Since the early type seems 
to differ from Snowflake only in size and earliness, and is probably 
inherited without special complications, the available progeny of early- 
type parents are included in the totals. The progeny of all parents 
recognized as belonging to other aberrant types are omitted. The 
second column under "Percentage of mutants" omits doubtful types 
and individuals, but includes some individuals for which some doubt 
was indicated in the original records. One rare type of 1911, large- 



Table 2 
Aberrant types: occurrence among progeny of SnoicflaJce and early parents. 
Apparent selective elimination at or after germination in 
field-sown cultures." 







Percentage of apparent mutants 


Cultures 


Progeny examined'' 














AH counted 


Doubtful omitted 


Greenhouse, 1910 


338 


5.03 ^ .82-^ 


4.14 -+- .77 


Field, 1911, seed 








house-sown 


2072 


5.31 ± .33 


4 63 ± .31 


All above 


2410 


5.27 + .31 


4,56 ^ .29 


Same,Snowflake par- 








ents only 


1364 


4.33 ± .41 


3.74 ± .38 


Field,1911,seed field- 








sown (parents all 








Snowflake ) 


3927 


2.34 ± .24 


1.55 ± .22 



" Germination in greenhouse-sown lots, counting only plants examined for 
type, 93.2 per cent; in field-sown lots, 4.5.1 per cent. 

•> Including some plants of uncertain type, indicated for some lots (wlien 
apparently not Snowflake) in tables 1 and 3. 

' For the calculation of these probable errors the percentages on the third 
line are used as p. 

leaved, here omitted, has proved to be genetic, but its deterniinatiim 
in these cultures was in general uncertain. A stricter criterion for 
the second column, elimination of all individuals not considered posi- 
tively determined, was used in the calculations for the table.s for the 
inheritance of the separate mutant types. 

Evidently the more rigorous field conditions of 1911 eliminated 
many of the "mutants" at or soon after germinaticm. The "coefficient 
of mutability" with good germination, as was the ease with the un- 
selected cultures of 1908. seems to be near 5 per cent, a surprisingly 
high figure if immediate true mutation is responsible. 

Before the aberrant types are considered separately, we may 
examine (table 3) a detailed illustration of their occurrence in lai'ger 
cultures. It seems probable, from this evidence, that any descendant 
of 'WG9 was capable of producing any of the mutant types so far 



MITATIOX IX MATTUIOLA 



233 



>> 



3 3 
I I 



Field lot 






Generation 1 



O 

o 



O 



O 



Generntion 2 









CJeneration 3 






Total progeny of 
determinable type 



H-tOw H-^: tOtCH-: tC: tCCOWi—: k-: H-H-h-i— 



Smooth-leaved 



Small-smooth- 
leaved 



Crenate-leaved 



Semi-crenate- 
leaved 



Pointed-crenate- 
leaved 



Medium-smooth- 
leaved 



into: »-' ten-* : •-- ; tO <— h- : i-" : i— h- : 



Narrow-leaved 



COH-: to 



Narrow-dark- 
leaved 



Slender 



Small-eonvex- 
leaved 



Compact 



Curly-leaved 



Pointed-Iight- 
leaved 



Large-leaved 



.-0 • ■ -o ■ 



Medium-large- 
leaved 



Large-thick- 
leaved 



Small stout- 
capsuled 



Jagged-leaved 



CC04iOCCjTtsiOCnC:i«50i^**'rf^CO>t»tO>— 'Ci00aiCOrfi.CCtOtnCntsSCO 



All counted 



OiOCCOOCntOOWCntOtt^CC*».tC4^tOH-Cn'^CnCC4^WtOCnrfi.i--CO 



Doubtful 
omitted 



(911 



234 



MISCELLANEOUS STUDIES 



discovered ; the occurrence of the various types suggests a random 
distribution among the progeny lots. This conclusion is confirmed, 
and extended to 062, by the field-sown lots of 1911. 

Various parents belonging to mutant types have given other 
mutant types among their progeny. There is some reason, as table 4 
indicates, to suppose that parents of the early type have a more 
marked tendency to produce these other types than have Snowflake 
parents.' 

Table 4 

IDIO and 1911F; sown in greenhouse. Apparent mutants among descendants 

of WG9-C10 and other ancestors, comparing early parents (pure or 

heterozygous) with Snowflake parents. 





Type of parent 


Progeny 


Ancestry 


Total 
examined 


Percentage of mutants 




All counted 


Doubtful omitted 


WG9-C10 

Pure Snowflake 

Both 

Both 


1 Early 

( Snowflake 
Snowflake 
Snowflake 
Both 


1046 

558 

806 

1364 

2410 


6.50 ± .47" 

4.30 ± .64 
4.34 =t .53 
4.33 ± .41 
5.27 ± .31 


5.64 ± .44 

3.41 =»= .60 
3 97 ± .50 

3.74 ± .38 
4,56 ± .29 



" For the calculation of these probable errors the percentages on the last line 
are used as p. 



Characteristics and Heredity op Mutant Types 
1. THE EARLY TYPE 

So far as is known, WG9-C10 (figs. 1, 2) was the only apparent 
mutant of the early type in the cultures. Since, however, this 
type visibly differs from Snowflake only or mainly in quantitative 
characters, it cannot be positively identified without comparative 
progeny tests, and therefore may have been represented by mutant 
individuals not used as parents. WG9-C10 was much smaller pro- 
portionately than were its progeny ; this difference was probably due 
to an embryonic abnormality, early blind termination of the main 
axis, which was occasionally observed elsewhere and probably occurred 
in this case. Plants of this type, as compared with Snowflake, are, in 
general, fewer-noded, smaller, and earlier in blooming. 

The principal data from the cultures of 1908 are shown in tables 
5 and 6, which also indicate the later conclusions as to the segregation 
of the early type in the cultures of this year ; figures 3 and 4 illustrate 



8 Inspection of the data in detail indicates that this difference is not due to 
the possible tendency in parents grown in the warm house to more frequent 
apparent mutation. 



[921 



MUTATION IN MATTHIOLA 



235 



Table 5 
Cultures of 190S. Time from sowing to emergence of corolla of earliest flower 
of primary cluster. Frequency distributions.'^ 





Singles 


Doubles 




Housfi C 1 


House M 1 


House W 


House C 


House M 1 


House W 


Parents; 


WG9- 
ClO 


Rest 


WG9- 
ClO 


Rest 


WG9- 
CIO " 


est 


WG9- „ 
€10 R 


est 


WG9- 
ClO 


Rest 


WG9- 
ClO 


Rest 


Da:,.- '' 


























110 






It 




















111 






It 






















112 




























113 




























114 




























115 




























116 








1 










1 










117 










It 


















118 






It 


2 




















119 








3 




















120 


It 






4 




















121 






It 


2 












1 




1 


122 








3 
















2 


123 








8 


It 








1 


1 




2 


124 






1 


4 












1 




') 


125 








7 


It 










5 


r 


3 


126 








16 












7 




7 


127 








3 


"it 


2 








9 




2 


128 








4 




3t 








8 




5 


129 








7 


It 


4 








8 




7 


130 








1 


It 


3 








12t 




4 


131 




i 




2 




4 






2 


12 




3 


132 


It 






1 




2 








7 




8 


133 


Ift 






1 


1 










4 




7 


134 


1 


•2 




2 




1 








2 




7 


135 




4 




4 




4 








6 




6 


136 




1 


1 


1 




3 


1 










4 


137 




7 




2 




3 




3 




1 




2 


138 




10 




1 




9 




4 




1 




1 


139 




18t 




1 


1 


2 




8 




1 




3 


140 


1 


7 




It 




4 


1 


3 








3 


141 




10 








1 


1 


9 




1 




3 


142 




4 











1 


5 




1 




1 


143 




4 






1 


5 


2 ] 











2 


144 




4 








2 




9 








2 


145 












3 




6 








3 


146 














1 


5 








2 


147 
















4 










148 












2 




1 








i' 


149 












2 




1 










150 




l' 








1 




2 










151 




1 












1 








1 


152 
























2 


153 




i 




















1 


154 


























155 




1 












l' 








1 



•Daggers (t) indicate the position and number of apparent mutants. Double 
daggers ({) indicate inheritance of parental type (here, early); all single progeny 
of WG9-C10 here reported have been tested for inheritance of this type. The 
conventional statistical constants corresponding to the house totals of tables 5 
and 6 have been published (Frost, 1911); the means for flowering given there 
are too high by one half-day. 

^ To time of observation (upper limit of one-day class). 



[931 



236 



MISCELLANEOV.'i STUDIES 



Table 5. Cultures of 1908 {Continued) 









Siiif 


■les 










Doubles 








House C 


House M 


House W 


House C 


House M 


House W 


Parents: 


WG9- 
CIO 


Rest 


WG9- 
CIO 


Rest 


WG9- 
ClO 


Rest 


WG9- 
ClO 


Rest 


WG9- 
ClO 


Rest 


WG9- 
ClO 


Rest 


Days '' 
156 

157 
158 
159 
160 
161 
162 
163 
164 
165 
166 
167 
168 
169 
170 
171 
172 
173 




It 




.... 










E 






i' 

It 
.... 



° Daggers (t) indicate the position and number of apparent mutants. Double 
daggers (}) indicate inheritance of parental type (here, early); all siiirjlc progeny 
of WG9-C10 here reported have been tested for inheritance of this type. The 
conventional statistical constants corresponding to the house totals of tables 5 
and 6 have been published (Frost, 1911); the means for flowering given there 
are too high by one half-day. 

*■ To time of observation (upper limit of one-day class). 

the difference in earlincss between the early and Snowtlake types. The 
parents gronped under "rest" include CG2 and WG9 tliemselves, with 
four progeny of the former and eight of the latter. Of these fourteen 
parents, not one has produced exceptionally few-noded jirogeny like 
those of WG9-C10. 

Apparently WG9-C10 wa.s heterozygous for a "few-nodedness" 
factor not carried by any of the other parents tested. Neither in 
the 1907 cultures nor in the 1908 cultures now under consideration 
did the data siiggest that WG9 itself was similarly heterozygous. 
Tables 5 and 6 include the first 30 progeny of "WG9, for each hou.se, 
as arranged at the lirst transplanting," 88 plants altogether; including 
the remaining plants, mainly weak or abnormal at transplanting, the 
total is 116. One of the F, plants (WG9-syn3-M10) was very sug- 
gestive of the early type, but (tables 12 and 13) it gave only Snow- 
flake progeny in a small test. 



!> See page 89. Two plants not jiroducing a normal main inflorescence are 
omitted. 



1941 



.1/; r Alios IS M.ITTIIIULA 



237 



Table G 

Cullures of 190S. Number of main-stem internodes bcloic first flower-bearing 
node. Frequency distributions.'- 





Singles 


Doubles 




House C 


House M 


House W 


House Q 


House M 


House W 


Parents: 


WG9- 

ClO 


Rest 


WG9- 
ClO 


Rest 


WG9- 
ClO 


Rest 


WG9- 
ClO 


Rest 


WG9- 
ClO 


Rest 


WG9- 
ClO 


Rest 


InternodeH 


























16 


It 
























17 


























18 


























19 


I'tt 
























20 


It 












i' 












21 






2tt 




















22 






It 








1 




r 








23 


















1 








24 
















9 










25 


1 


2t 


It 


1 






2 


25 










26 
















29 




1 






27 


1 


i 




r 






1 


22 




2t 






28 




17 












6 




9 


1 




29 




24 




1 












14 






30 




13 




1 








l' 


2 


22 




i" 


31 




8 




2 




.... 








27 






32 




2 




7 












5 






33 




1 




15 


It 










3 






34 






1 


16 












4 




i' 


35 




2 




19 


It 














5 


36 








4 


It 










1 




6 


37 








1 


It 














8 


38 








8 


















5 


39 








3 


















13 


40 








1 


















6 


41 






1 


1+ 


















8 


42 




It 






It 
















6 


43 












If 














12 


44 


























9 


45 










It 
















6 


46 












4 














3 


47 












3 














3 


48 












4 
















49 










i' 


3 














i' 


50 












6 
















51 










i' 


3 














2t 


52 












10 














1 


53 












6 
















54 












2 














2 


55 










1 


3 
















56 












7 














i 


57 












8 
















58 












1 
















59 












1 














\ 


60 












3 
















61 




























62 












r 

















' See note o to table 5. 



[95] 



238 • MISCELLANEOUS STUDIES 

The differentiation of the eai'ly race is very marked ; with the 
singles, in fact, the later cultures indicate no case of overlapping in 
the 1908 cultures, in either character, between extracted pure Snow- 
flake and pure or heterozj-gous early. The total sterility of the doubles 
necessarily leaves their constitution somewhat in doubt. 

The ci;ltures of 1908 so far suggest that WG9-C10 was a mutant. 
To be reasonably certain, however, we must have further evidence 
(1) on the fact and mode of inheritance of the suppo.sed new type, 
and (2) on the possibility that either WG9 or some other plant of 
the cultures of 1906 brought the character into the cultures. We shall 
now consider somewhat extensive evidence bearing on these points, 
concluding with a special test of the possibility of vieinism. 

When I la.st saw the warm-house plants of 1906, three were known 
to be singles, and all but two of the rest were recorded as certainly 
or probably doubles. Seed was secured from these three singles only, 
and presumably no other singles occurred in the house. Since this 
seed was all from unguarded flowers, we must con.sider the possibility 
that WSl or WLIO, the other warm-house singles, brought the early 
factor into the cultures. It is also barely po.ssible tliat pollen was 
brought to WG9 from some plant not in this greenhouse. 

These two parents were tested in supplementary cultures, in house 
C in 1907, and in house W in 1908. The 1907 progeny averaged 
slightly earlier than those of other parents, but this may have been 
due to their position, whieh was much nearer a partition separating 
the house'" from a warm greenhouse. Unfortunately the internodes 
were not recorded. 

In the 1908 cultures these lots were potted two days later than 
most of the other lots and one day later than the WG9 lot, and for 
some unknown reason the WLIO lot wilted badly for some days. The 
parents in question gave singles (16 and 11 plants respectively) which 
when compared with progeny of CG2 and WG9 (23 and 15) might 
suggest that the parents were heterozygous for the early type. The 
results with the similar numbers of doubles decidedly disagree with 
these, and suggest that cultural accidents produced the differences; 
the WSl lot was not exceptional, while all the WLIO progeny were 
grouped near the lower end of the range of the other lots. In view of 
all the facts, the data hardly deserve tabular presentation, but they 
raise a question requiring further study; a later test is reported below. 



10 A temporary substitute for the regular house C. 



MVTATION IN MATTHIOLA 



239 



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[97] 



240 



MISCELLANKOrH STUDIES 



In the cultures of 1910 and 1911F. all the 1908 progeny of WG9- 
ClO were tested. On account of the variable nature of the quanti- 
tative character involved, an elaborate study was necessary. Only 
small eultui'es could be grown in the greenhouse ; these were supple- 
mented by larger lots in the field in 1911, but inhibition of flowering 
by the hot summer, together with the effects of disease and soil varia- 
tions, made the field results erratic and necessitated special methods 
of treatment of the evidence. 



singles 
Doubles 



• 

_ _ 

_^ _^ ^ _ _ 

• ^^s= ; 

— =^ — ^^=1=111^^ — ,^:z:_!_=^ zzz^^^^ 

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09 



WCI9 

Ancestry 



Chart 1. Cultures of 1910. Internodes: parental values and progeny means 
(respectively shown by dots and lines) for progeny lots 1 to 17, omitting 
aberrant progeny. Parental values should be compared only for the same house. 



Table 7 gives the available data for the parents of the 1910 cultures, 
and the numbers of progenj^ available for quantitative data. The 
order of the pedigree numbers here is the same as that of the progeny 
lots on the greenhouse bench. For convenience, the 1910 tests of other 
mutant types, together with tests of several Snowflake parents, are 
included in the table (lots 18 to 30). 



[981 



MITATIOX l.\ MATTIllOLA 241 

The plants were grown in house C of the previous work. Two or 
three plants (one shown in fig. 25) were extremely vigorous, pre- 
sumably because of some accidental soil difference ; aside from these, 
a few apparent mutants, and a few plants otherwi.se abnormal, the 
plants were fairly uniform except where heterozygosis was to be 
expected. 

The data for time of flowering, as with the 1908 cultures, show the 
same main features as the internode data, and only the latter will be 
considered in detail. The types were again more widely different in 
internodes than in earliness, a fact which seems to indicate that the 
early type grows more slowly than Snowflake. 

So large and so regular are tlie differences in internodes that the 
means of the.se very small lots seem worthy of presentation (chart 1).'^ 
Apparently the few-noded character was carried, among the nine 
parents descended from WG9-C10, by all except the three parents 
having the highest number.s in their respective houses. 

Tables 8 and 9 give the internode frequencies for the singles and 
doubles respectively, by separate progeny lots and by groups of similar 
ancestry. The range of variation for the check lots, omitting the 
indicated apparent mutants and other apparently abnormal plants, is 
rather surprisingly small, as is the case with the cool-house cultures 
of 1908. The three late progeny of WG9-C10 give lots closely corre- 
sponding in range to the check lots, only one individual falling below 
the range of the combined check lots. The six early and medium 
progeny of WG9-C10, on the other hand, give distributions of far 
greater range than do the check parents, extending to much low-er 
values. 

Tables 10 and 11 give the ordinary statistical constants for the 
grouped lots. The mean ninnber of internodes, for both singles and 
doubles, is about 25 per cent lower in the progeny of the six few- 
noded parents, the difference being not far from ten times as great as 
its probable error. The increase in variability with the progeny of 
the early parents is also striking, and the difference is about five to six 
times its probable error. With time to flowering, it may be noted, the 
differences are similar to those with internodes, but somewhat less 
marked in the ca.se of the mean ; the flowering data are not given here. 

It is plain that the previous conclusion as to the heterozj-gous nature 
of WG9-C10 is sustained. The elimination of the apparent mutants 



11 Calculated with the apparent mutants ami four other apparently aljnornial 
plants eliminated; see tables 8 and 9. 



[991 



242 



MISCELLANEOUS STUDIES 



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MUTATION IN MATTEIQLA 



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[1021 



MUTATION IN MATTIIIOLA 



245 



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246 



MISCELLANEOUS STUDIES 



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[1041 



MVT.triON IN MATTHIOLA 247 

and the other abnormal plants presumably gives a better comparison 
as to mean and variability, but the conclusion is the same in either 
ease. The three many-noded (late) parents descended from WGO- 
ClO give no definite indication of being genetically different from the 
"check" lots not descended from WG9-C10, while the variability con- 
stants are sufficient, taken alone, to make probable the genetic differ- 
entiation of the fewer-noded progeny of WG9-C10. Apparently all 
the fewer-noded progeny of WGQ-CIO that were tested — seven, when 
WG9-C10-C10, a erenate-leaved apparent mutant (tables 12 and 13), 
is included — were either simplex or duplex for presence of an earliness 
factor or factors. 

The variabilitj^ of all the thirty progeny lots, taken together, is 
high, as might be expected, though decidedly below that of the progeny 
of early parents. This high variability is due only in very small part 
to the progeny of the five or six supposedly mutant parents ; the last 
thirteen lots, alone, are mucli less variable than the mixed early lots. 
The portion of the cultures containing these progeny lots from 
aberrant parents was conspicuous for irregularity of germination, and, 
on the whole, a relatively low rate of germination. 

A few of the last thirteen lots give more evidence bearing on the 
origin of WG9-C10. The early WG9-.syn3-M10 (tables 12 and 13) 
gives no evidence of genotypic differentiation from its ordinary sib, 
WG9-syn3-Mll ; WSl-WjlG, another phenotypically early parent, 
also failed to transmit earliness to its progeny. CG2-C2-C6, on the 
other hand, although itself an ordinary plant, shows a rather sus- 
picious tendency to the production of early and few-noded progeny, 
but better evidence would be required for any positive conclu-sion. 
'WG9-C10-C10 appears, from the data in tables 12 and 13 and from 
observation of the flowering of plants of the next generation in the 
1911H cultures, to have been heterozygous for the early type, as well 
as for the erenate-leaved type. We find in this test no definite indi- 
cation that the early type has appeared elsewhere than in WG9-C10 
and its descendants. 

The P, progeny of WG9-C1, an abnormal plant whose F^ progeny 
were unusually and uniformly early but not few-noded, have been 
included with the other check lots without question. This treatment 
seems justified by the flowering data, which do not indicate any 
repetition of the precocious development of the first-generation plants ; 
the peculiarities of the P; cultures, if not a mere cultural accident, 
presumably depended on the very abnormal development of the parent. 



[1051 



248 



MISCELLANEOUS STUDIES 



Table 12 

1910, greenhouse, lots 18 to SO. Number of main-stem internodes below first 
flower-bearing node. Frequency distributions for singles.'^ 



Ances- 
try 



Gen. 1 


CG2 


WG9 


wsi 


WLIO 


Gen. 2 


02 


W4 


syn (M) 3 


C228 


W2 


CIO 


W2 


W7 


W2I6 


W225 


W22O 


Gen 3 


CG 


W3 


017 


MIO 


Mil 




M7 


010 


W2 


05 








Ivter- 




























nodes 




























21 


1 















It 












22 
















It 












23 


















It 










24 


i 


























25 




























26 




1 















it 


2tt 








27 


i 






i 










It 


It 


2 




2 


28 


1 


2 


i 




i 








It 




4 


i 


3 


29 






1 


2 


2 


i 






1 




2 


3 


30 




1 


3 


3 


2 


1 


1 


It 


1 










31 





1 




1 




1 
















32 












1 


i 








1 






33 




1 






It 


















34 






i 






i 
















35 




























36 












1 
















37 




























38 


























1 


39 














It 














40 






i 






















41 












It 

















42 




























43 





























44 














It 
















' See table 7 and notes to tables 5 and 8. 



Table 13 
Same as table 13, for doubles.' 





Gen. 1 


CG2 


WG9 


wsi 


WLIO 


.Ances-« 

try 1 


Gen. 2 


02 


W4 


syn (M) 3 


C228 


W2 


010 


W2 


W7 


W2I6 


W225 


W220 




Gen. 3 


C6 


W3 


017 


iMlO 


Mil 




M7 


CIO 


W2 


OS 










^ Inter- 






























nodes 






























16 
















1 














17 
















2 














18 






























19 


1 




























20 






























21 
















3 














22 


1 








2 






2 














23 




1 




2 






i:; 








3t + 


i 






24 


2 


1 










1:: 




It 






2 






25 


4 








i 


3tt 




2 


It 


it 


i 


1 


i 




26 


2 




2 


2 


1 








1 




2 


It 






27 




2 




1 


2 


2 






3 


3 


1 


2 






28 






1 




1 


1 






2 


5 




1 






29 






2 


1 




1 








2 










30 














3tt 
















31 






























32 






i 








1 






it 










33 






























34 














i 




1 











° See table 7 and notes to tables 5 and 8. 



MrTATIOX rx MATTBIOLA 



249 



with its aborted main axis and very late production of a tiowering 
shoot. 

Table 14 shows the general plan of the house-sown field cultures 
of 1911. The progeny of WG9-C10 were arranged as before in the 
order of their numbers of internodes for each house of the 1908 cul- 
tures, beginning with the lowest numbers. The parental values for 
tiowering and internodes are the values indicated by "$" in tables 5 

T.\BI,E 14 

1911; field, plants transplanted from greenhouse. Ancestry, seed, and 

numbers of progeny." 









Number of 


Numbers of plants 


"or data 


Lot 


.\ncestry 


Seeds 


plants alive 

33 days after 

sowing 


on mutation and f 


owering 




Gen. 1 


Gen. 2 


Gen. 3 


sown 


Totalb 


Singles 


Doubles 


^) 






C5 


/C8 
\C10 


80 


79 


77 


34 


43 






71 


71 


70 


36 


34 


31 








rc2 


80 


80 


79 


39 


39 


4 , 

5 1 






CIO 


C5 


80 


79 


78 


40 


38 






■ C8 


80 


79 


78 


35 


43 


6J 








CI 


80 


78 


76 


36 


40 


7\ 






C5 


/W18 
\W24 


80 


79 


77 


37 


40 


8/ 






80 


76 


75 


41 


34 


91 
10 










M4 


SO, 26 


77 


76 


30 


45 










M9 


80 


80 


78 


36 


41 


11 1. 

12 '' 






CIO 




M6 


80,63 


77 


77 


34 


42 










M2 


80,7/ 


78 


77 


36 


40 


13 

14 J 










M7 


80 


80 


80 


37 


42 










M8 


80 


74 


70 


33 


37 




WG9 


















15 1 
16/ 






C9 


/C3 

iC7 


80 
80 


78 
76 


78 
75 


30 
32 


48 
43 


171 












W6 


80 


74 


70 


31 


39 


18 












W4 


80, ^/ 


70 


65 


26 


38 


19 












WU 


80 


78 


76 


34 


42 


20 












W9 


80, 1.9 


76 


72 


24 


47 


21 


■ 






CIO 




W5 


SO 


79 


75 


33 


42 


22 












W8 


80, 14 


76 


74 


36 


36 


23 












W7 


SO 


75 


72 


32 


40 


24 












W3 


80 


73 


71 


37 


34 


25 J 












WIO 


74 


72 


66 


32 


34 


26 






CIO 




80 


60 


59 


. 27 


32 


271 
28/ 






C9 


/WIO 

\W24 


80 


74 


73 


33 


39 






80 


80 


78 


32 


45 



' For plan of arrangement and parental data, see page 86 and tables 5 and 6. 
Seeds from unguarded flowers are indicated by italic figures; where two numbers 
are given the first is the total. 

•> Including twelve plants (all late mutants) with which determination of the 
form of flower was impossible. 



[1071 



250 



MISCELLANEOUS STUDIES 



and 6, in the order there given, except that the arrangement by inter- 
nodes reverses the two-day difference in earliness of the parents of 
lots 19 and 20; for convenient comparison, the parental and parent- 
lot internode values are included in table 19. 

Two progeny lots were set in each of the fourteen rows; probably 
the soil was less favorable at the east end of the plot, and hence for 
the even-numbered lots, at least in about the last seven rows out of the 
fourteen. 

The plants were beginning to grow very rapidly when moved to the 
field. On account of deficient soil moisture and excessive heat, the 
transplanting was slow and in part purposely delayed, covering a 
period of five days. Lots 21 to 28 were set three days later than lots 



80 






























































70 


OPO 




































(JO 



































































40 




?o 








































































































in 

















































1 


2 


3 


4 


5 


6 7 8 9 


10 


11 


12 


13 


14 


(C) 






(C) 




(C) 
Row number 










(C) 



Chart 2. 1911, field; lots transplanted from greenhouse. Percentages of 
progeny lots not flowering by November 3, for singles. Apparent mutants and 
injured plants eliminated. Odd-nurabered lots represented by solid line. (C) 
indicate check rows. The curves'are broken between rows 10 and 11, where a 
cultural difi^erence enters. 

11 to 20, and the later loss of roots resulting seems, in spite of rain 
coming the next day, to have seriously delayed flowering. Lots 1 and 2 
wilted badly after transplanting, and some difference in soil con- 
ditions in the flats, rather than a genetic difference, was doubtless 
responsible for the exceptional lateness of these lots. Lot 20 lost an 
exceptionally large leaf area as a result of transplanting. A fungus 
disease (a slow stem rot) was more common on lots 20 to 24 than 
elsewhere; it doubtless killed some young plants and delayed or pre- 
vented flowering in some other cases. Pos.sibly the soil was poorer in 
the later rows. 



[108] 



MUTATION IN MATTE lOLA 



251 



Table 15 
1911, Held; plants transplarited from greenhouse. Plants alive November 3, 
not having flowered. Singles. 







Nou- 


Non-flowering, 




Non-flowering 


Non-flowering, 


Row 


Lot 


flowering 
plants 


Snowflake and 
early types » 


Lot 


plants 


Snowflake and 
early types" 


1 


1 


27 


26 


2 


29 


28 (27) 


2 


3 


5 


2 


4 


7 


5 


3 


5 


9 


9 


6 


11 


11 


4 


7 


7 


5 


8 


17 


17 


5 


9 








10 


2 


2(1) 


6 


U 


1 





12 


9 


7 


1 


13 


19 


18(17) 


14 


20 


19 


8 


15 


12 


12 


16 


14 


14 


9 


17 


1 


1 


18 


8(7?) 


7(6?) 


10 


19 








20 


3 


3 


11 


21 


8 


8 


22i> 


11 


10 


12 


23 


21 


20 


24 


23 


23 


13 


25 


IR 


M (12) 


26 


14 


12 


14 


27 


23 


22 


28 


24 


24 



■ Omitting non-flowering apparent mutants. For the numbers in parenthesis, 
"doubtful mutants" are classed as mutants. Two plants accidentally seriously 
injured, in lots 14 and 25, were counted out with the mutants. 

" The stem-rot disease (see p. 108) was evidently worst in lot 22; some two or 
three of the worst infected plants (included above) were nearly or quite dead 
by November 3. 

Table 16 

Same as table 15, for doubles. 



Row 


Lot 


Non- 
flowering 
plants 


Non-flowering, 

Snowflake and 

early types* 


Lot 


Non-flowering 
plants 


Non-flowering. 

Snowflake and 

early types'* 


1 


1 


4 


2 


2 








2 
3 


3 
5 


3 
3 


1 

3 


4 
6 


1 




1(0) 



4 


7 


3 


2(1) 


8 


3 


1 


5 
6 

7 


9 
11 
13 


2 

4 





2(1) 


10 
12 
14 





1 





1 


8 


15 


2 


2 


16 


6 


5 


9 
10 
11 
12 
13 


17 
19 
21 
23 
25 


1 


3 
5 
1 




1 
5 
1 


18 
20 
22 
24 
26 


3 
2 

1 
4 
7 


3(2) 

2 

1 

4 

5 


14 


27 


1 


1 


28 


10 


8 



' See notes to table 15. 



[109] 



252 



MISCELLANEOUS STUDIES 



Altogether, these cultures are doubtless much less reliable for their 
size thau the greenhouse tests of the early type, but they nevertheless, 
with clue consideration of the points just mentioned, seem to permit 
of fairly safe conclusions for most of the parents. 

The plants were examined for flowering every other afternoon from 
July 4 to November 3, inclusive (73 to 195 days from sowing) . A very 
large part of the plants flowered in July, some in August, and a few 
still later. Evidently the high summer temperature largely iiiliibitcd 
flowering ; many of the singles and a few of the doubles entirely failed 
to flower. 



uu 




































































8(J 
































70 

fin 






fJ/£ 


V 
























































50 


ODD 
































30 






























































20 











































































\ 


2 


3 


4 


5 


6 7 8 9 


10 


11 


12 


13 


1-1 


(C) 






(C) 




CC) 
Row number 










(C) 



Chart 3. 1011, field; lots transplanted from greenhouse. Percentages of 
progeny lots with primary cluster flowering or aborted by October 10-16, for 
singles. Lines as in chart 2. 

Figures 5 and G .show the plants in July. Growth was usually 
vigorous through the sea.sou, but the internodes were very short, the 
branches numerous, and the region of the terminal inflorescence often 
abortive, so that determination of the number of main-stem internodes 
was not practicable. The emergence of the earliest corolla on the plant 
was recorded at the bi-dinrnal oliservations. and at two periods during 
the season the aborted primary clusters were noted. 

The data show very definitely the transmission of "earliness" by 
the fewer-noded progeny of WG9-C10. Tables 15 and 16 show the 
numbers of plants alive, without having flowered, on November 3 ; the 
figures are thus a measure of lateness. The two progeny lots in each 
row are given one line in each of the tables, in order to facilitate 
separate eoniparison of the fourteen lots in eaeli end half of the jilot. 



[1101 



MriATIOX IX ilATriUOI.A 



253 



The last cohimn, with the apparent mutants omitted, no doubt gives 
the best comparison. The data for the singles, reduced to percentages, 
are also given in chart 2. 

The doubles, which are often earlier to flower than the singles under 
unfavorable climatic conditions, flowered so generally that table 16 
presents no significant differences. The singles (table 15), however, 
give definite evidence of segregation ; the lots in row-s 2, 5, 6, and 9 to 
11 all show a tendency to early flowering. Lot 26, consisting of Fj 

Table 17 

1911, field; j}Jaiits transplanted from greenhouse. Singles with primary 
inflorescence flowering or aiorted as indicated.'^ 



Row 


Lot 


Aborted by 
July 29 


Flowering or 
aborted by 
Oct. 10-16 


Lot 


Aborted by 
July 29 


Flowering or 
aborted by 
Oct. 10-16 


1 


1 








2 





0(2) 


2 

3 


3 

5 


12 (13) 

2 


19 (22) 
2 


4 
6 


20 

4 


24 (26) 
8(9) 


4 


7 


2(3) 


3(4) 


8 


1 


1(2) 


.5 
6 

7 


9 
11 
13 


22 
25 

1 


27 

29 (30) 
2(4) 


10 

12 
14 


26 
17 

2(3) 


33 
22 

2(3) 


8 


}5 


4 


5(6) 


16 


0(1) 


1(2) 


9 
10 
11 
12 
13 


17 
19 
21 
23 
25 


19 (20) 
25 (27) 

4 

2 




20 (23) 
29(31) 

6(8) 
3(4) 
3(4) 


18 
20 
22 
24 
26 


9 
U 

7 
1 
3 


12 

12 

9 

1(2) 
4(5) 


14 


27 


1 


3(4) 


28 





0(1) 



"In this table and also in table 18 the numbers in parenthesis include the 
probable but somewhat doubtful cases. 

progeny of "WG9-C10, is decidedly earlier than the adjacent lots. 
Lot 25 also appears early, however. 

Tables 17 and 18 give a direct measure of earliness, relating to the 
primary inflorescence alone. The clusters visibly aborted were in 
general relatively far advanced, and those aborted at the earlier date 
correspond to decidedly early flowering; consequently the flowering 
and aborted clusters are classed together as early. Chart 3 gives the 
percentages for singles. 

Here the data for the doubles show fairly consistent differences in 
the number aborted at the earlier date, while the October totals are 



[111] 



254 



MISCELLANEOUS STUDIES 



less regular. There are contrasts similar to those of table 15 up to 
lot 26, which is late, while the check lots 27 and 28 are early. The 
singles show the type differences very strikingly throughout lots 1 
to 20, while lots 21, 22, and 26 give less positive indications of the 
pre.sence of the earl.y factor. 

Table 19 gives the numbers of singles flowering, in primary in- 
florescence or elsewhere, by November 3, when growth had practically 
stopped. The indications are in general the same as with the data 
already discussed, with better evidence than usual that lots 21 and 22 

Table 18 
Same as table 17, for doubles.' 



Row 


Lot 


Aborted by 
July 29 


Flowering or 
aborted bv 
Oct. 10-16 


Lot 


Aborted by 
July 29 


Flowering or 
aborted by 
Oct. 10-16 


1 


1 


15 


30 


2 


6 


22 (23) 


2 
3 


3 
5 


23 
12 


33 (34) 
29 (30) 


4 
6 


21 
16 


35 
30(31) 


4 


7 


17 


30 


8 


8 


22 (24) 


5 
6 

7 


9 
11 
13 


25 

25 (26) 
16 


41 

40(41) 
28 


10 
12 
14 


24 
23 
22 


41 
40 
31 


8 


15 


27 


37 (39) 


16 


11 (12) 


29 (32) 


9 
10 
11 
12 
13 


17 
19 
21 
23 
25 


20 
21 
22 

16(17) 
17 


35 

41 (42) 
35 

27 (28) 
25 


18 
20 
22 
24 
26 


20 (21) 
21 
18 
10 
9 


32 (33) 
42 (44) 
27 (28) 
16 (17) 
15 


14 


27 


21 


29 (30) 


28 


20 


25 (27) 



■ See note to table 17. 

po.ssessed the early factor. The mean time of flowering is irregular, 
but shows some effect of the earliness factor. Lot 26 is late as to 
number flowering, but early as to mean. 

Table 20, for doubles flowering by August 1, no doubt gives more 
reliable ipeans; these means disagree with our scheme only in lot 26 
and perhaps lot 22. 

According to tables 17-20, the fewer-noded check parent of each 
check row has usually given the earlier progeny. In fact, the agree- 
ment of parental and progeny differences, throughout the cultures, is 
decidedly remarkable. It is unfortunate that the later parents were 
always placed in the east half of the row, especially in view of the 
fact that there was indication of important differences in soil and 



[1121 



MUTATION IN MATTHWLA 



255 



Table 19 

1911, Held: plants transplanted from greenhouse. Time from sowing to 
emergence of earliest corolla. Singles. 





Parent-lot 




Parental 


Progeny flowering 
by Nov. 3 




Parental 


Progeny flowering 
by Nov. 3 


Row 


internode 
mean 


Lot 


internode 
number 






Lot 


internode 
number 






Number 


Days to 
flowering 


Number 


Days to 
flowering 


1 


29 60 


1 


29 


7 


147 14 


2 


32 


7 


128.57 


2 
3 


21.40 


3 
5 


16 
25 


34 
26 


91.94 
119.46 


4 
6 


20 
27 


33 
25 


105.45 
104.08 


4 


49.57 


7 


46 


30 


103 13 


8 


54 


24 


105.67 


5 
6 
7 


27.33 


9 
11 
13 


21 
22 
34 


30 
33 

18 


91.73 

98.85 
100 67 


10 
12 
14 


21 
25 
41 


34 
27 
13 


91.12 
108.30 
120.62 


8 


28.50 


15 


27 


17 


112 94 


16 


29 


18 


118.00 


9 
10 
11 
12 
13 


42 . 56" 


17 
19 
21 
23 
25 


33 
36 
42 
49 
55 


30 
34 
25 
11 
15 


100.27 
97.35 
129.36 
122.00 
136.40 


18 
20 
22 
24 
26 


35 
37 
45 
51 


18 
21 
25 
14 
13 


109.67 
117.81 
121.76 
151.57 
121.08 


14 


47.80 


27 


46 


10 


159.40 


28 


56 


8 


162.50 



• This parent-lot value does not apply to lot 26, which consists of progeny of 
WG9-C10 itself. 

Table 20 
Same as table 19, for doubles flowering by August 1. 



Row 


Lot 


Progeny flowering by Aug. 1 " 


Lot 


Progeny flowering by Aug. 1 


Number 


Days to flowering 


Number 


Days to flowering 


1 


1 


38 


90.26 


2 


33 


91 03 


2 
3 


3 
5 


36 
39 


80.22 
84.46 


4 
6 


36 
39 


80 00 
84 10 


4 


7 


36 


81.28 


8 


31 


84.32 


5 
6 

7 


9 
11 
13 


42 
42 
37 


75.86 

77.90 

• 84.32 


10 
12 
14 


41 
40 
35 


76.59 
80.25 
84 80 


8 


15 


46 


83.87 


16 


33 


85.21 


9 
10 
11 
12 
13 


17 
19 
21 
23 
25 


37 
42 
39 
33 
32 


' 80.43 
78.24 
85.95 
89.03 

88 56 


18 
20 
22 
24 
26 


34 
39 
30 
26 
21 


84.12 
83.85 
87.93 
88.85 
89.05 


14 


27 


35 


88.97 


28 


29 


90.28 



* Only 48 more doubles altogether flowered by November 3, and 23 of these 
were in the even-numbered lots 20 to 28. 



riisi 



256 



MISCELLANEOUS STUDIES 



probably in the incidence of disease, favoring the plants in the west 
half. The internode data of 1910, however, show a similar tendency. 
Small genetic differences are suggested, though it would be remarkable 
if they were so uniformly present in these plants of a single line of a 
usually selfed species, descendants of parents and a common grand- 
parent grown under glass. 

If such differences exist in the race, conceivably some combination 
due to cros.sing might simulate an early mutation. The evidence as a 
whole, however, does not favor such an origin for our early type ; it is 
widely divergent from the Snowflake type, and seems to depend on 
a single main factor difference from Snowflake. 

Table 21 
CuJtiires of 1913. Ancestry and parental data. 







Parental data 




Lot 


Parent 








Seeds sown 






Probable type 


Days to 
flowering^ 


Inter- 
nodes^ 




1 


WS1-W,16 


Snowflake" 


120 .'i 


38 


15 


2 


WG9-C10-W6 


Early 


116.5 


33 


15 


3 


WL10-VV.2 


Snowflake 


139.5 


51 


15 


4 


WL10-W.3 


Snowflake" 


120,5 


38 


15 


5 


WSl-W-1 


Snowflake 


141 5 


57 


15 


6 


WL10-Wa4 


Snowflake" 


12R.5 


38 


15 


7 


WL10-W..7 


Snowflake 


145.5 


54 


15 


8 


WG9-C10-W8 


Early 


129 . 5 


45 


15 


9 


WSI-W0I2 


Crenate-leaved"''' 


119.5 


34 


7c 



•Suspected before testing of belonging to the early type; first parent also 
tested in 1910. 

•" A heterozygote between the erenate-Ieaved and Snowflake types. 

' Probably open pollinated. 

'' All the parents grew in the same house at the same time. 

The essential feature of the supplementary cultures of 1912, since 
no seed of WLIO remained, was a test of two pairs of early and late 
progeny of WLIO (lots 3 and 4. 6 and 7, table 21), in comparison with 
two control lots — one (lot 2) from a known early parent, descended 
from "WG9-C10, and one (lot 5) from a late descendent of WSl. 
Incidentally, WSl-WJG and WGg-ClO-WS were retested, and the 
few available .seeds of WSl-W-,12 were used to test that phenotypieally 
early parent. 

The results are given in tables 22 and 23 and chart 4. The very 
low individual from "WSl-WolC came from a very weak embryo, and 
should be disregarded; the exceptionally high general range of this 
lot, which was also visibly behind all othei-s in development, was prob- 



1.1141 



MUTATION IN MATTHIOLA 



257 



Table 22 

Cultures of 19li. Number of main-stem internodes below first flower-bearing 
node. Frequency distributions for singles." 



' See note a to table 5. 



Cultures of 191S. 



Table 23 
Same as table SS, 



for doubles.' 





Gen. 1 


WSl 


WG9 


w 


1.10 


WSI 


WLIO 


WG9 


WSl 


Ancestry - 


Gen. 2 


Wo 16 


CIO 


W22 


W23 


Wol 


W2I4 


V 


f27 CIO 


Wo 12 


Gen. 3 




W6 












W8 




Internodes 

18 


it 
i' 

2 

1 

2t 


i' 

i' 

3 

i' 


1 

4 

1 




i ' 

3 
3 
1 






It 

".'. 1" 

2" 

3 1 
2 




19 








20 




21 




22 




23 . 




24 




25 




26 




27 


2 

1 

2 
1 




28 . 


u 

1 


29 


30 


31 




32 








33 




34 




35 













Gen. 1 


WSl 


WG9 


WLIO 


WSl 


WLIO 


WG9 


WSl 


Ancestry < Gen. 2 


Woie 


CIO 


Wo 2 


Wo 3 


Wol 


WoU 


Wo 7 


CIO 


W212 


Gen. 3 




W6 












W8 




Internodes 

12 


lA 

1 

2" 
3t 


1 

1 
1 

2 
2 
1 

i' 








i' 
i' 

3 

1 


i' 

1 

1 

1 

2 
3 


i 

2' 
2 

1 

2 




13 
















14 




15 




16 




17 




18 




19 




20 




21 




22 




23 


It 

3 
3 
2 




24 


1 

5 

1 




25 


2 
3 

1 


1 


26 


1 


27 




28 










It 


29 


30 




31 































" See note a to table 5. 



[1151 



258 



MISCELLANEOUS STUDIES 



ably due to some cultural accident, perhaps to an excess of moisture 
in this row of pots. 

The lots of plants may seem rather absurdly small for their pur- 
pose, but the uniformity of development here, with the marked normal 
divergence in internodes of the types in question, seems to justify a 
fair degree of confidence. Ten plants here were probably worth fifty 
in the field. 



31 






























I 


ingl 
oub: 


es 

68 










_ 





29 


























































i 


» 






















2.S 






















































O" 






'' 


































_ — . 


-— . 






■26 
25 

■s 

■g 24 

c 














1 


» 






























— . 


.__ 













1 













.__ 






































































































— •< 


•— 


21 






"""■ 


""" — 


































20 










































19 

IS 


















































































17 










































16 






( 


\ 



































w^iie W6 

I I 

wsi CIO 

WG9 



Wi2 



Wi.3 



Wsl 

I 
WSI 

Ancestry 



WiU 



W27 



will 



W8 

1 
CIO 

I 

WG9 



Wil2 

I 
WSI 



Chart 4. Cultures of 1912. Internodes: parental values and progeny means, 
shown as in chart 1. The true parental values are twice those indicated by the 
ordinate figures, which apply directly to the progeny values. 



This test, with that of 1910, shows very positively that WSl-WjlG 
was only phenotypically few-noded. Evidently WGO-CIO-WS, the 
parent of field lot 22, really carried the earliness factor, as was some- 
what doubtfully inferred from the field results; the five progeny of 
WS1-W„12, on the other hand, though from a fewer-noded parent, 
have values that make the presence of the earliness factor improbable. 

On the main point at issue the evidence seems satisfactory. Neither 
of the two very early and few-noded progeny of WLIO represented 



Mr 'I. ir ION IN MATrillOLA 259 

shows in its progeny any evidence of belonging to the early type ; the 
means are slightly lower than for the many-noded sibs of these parents, 
but far less so than with the parents descended from "W69-C10. 

We conclude, then, that WG9-C10 was probably a monohybrid, 
and that the early-bearing gamete entering into its composition was of 
unknown but presumably mutative origin. 

Most of the extracted late or many-noded parents may now be 
selected with practical certainty. WGQ-CIO-CS and CI (lots 5 and 6 
in the 1911P cultures) and WG9-C10-M7 and M8 (lots 13 and 14) 
were genetically very similar to the check parents, as has already been 
concluded for two of them from the greenhouse cultures; presumabh" 
they were pure Snowflake. 

The data for WG9-C10 itself (lot 26) seem to indicate that the 
results from the last eight lots are of very doubtful value ; still, they 
show, especially in the original individual records, some evidence of the 
earliness factor which must be present in part of the individuals. The 
poor and slow germination of the old seed available may have had an 
important influence on the result ; many of the early embryos may have 
been non-viable, and the seedlings may have been weaker than those 
from fresh seed. The 1911 data and observation of the plants in the 
field suggest that WG9-C10-W7, W3, and WIO (lots 23, 24, and 251 
are the only remaining extracted late parents, WG9-C10-W5 and W8 
(lots 21 and 22) carrying the earliness factor, as the four parents just 
preceding them in the cultures obviously did. Tables 22 and 23 con- 
firm this conclusion for WG9-C10-W8. 

It is presumably impossible to make a positive separation of the 
parents homozygous for the presence of the early factor. The green- 
house data suggest that WG9-C10-M4 was a pure early individual ; 
the field data (see lot 9) agree, and suggest that WG9-C10-M9 (lot 
10) and perhaps WG9-C10-M6 (lot 11) belong in the same cla.ss. 
WG9-C;iO-C2, C5, and CIO (lots 3, 4, and 40)'- were all evidently 
heterozygous. Of the parents grown in house W, it would seem that 
only WG9-C10-W11 (field lot 19) was homozygous early. We have, 
provisionally, for the available single progeny of WG9-C10 : 

House C House M House W Total 

Pure early 3 14 

Hybrid early 3 15 9 

Pure late 2 2 3 7 

20 



'2 Statistical data given for the last only for the 1910 cultures, not for this 
field lot. 



[1171 



260 MISCELLANEOUS STUDIES 

This corresponds well enough with the monohj'brid expectation of 
5 : 10 : 5 ; in fact, the deviation is just such as would be expected if there 
was occasional cross pollination of the unprotected flowers of WG9- 
ClO from Snowflake plants. The large proportion of evidently pure 
late parents is strong evidence for the monohybrid nature of WGO-CIO. 

The proportions of the two types among the doubles can only be 
estimated. The 1908 data suggest that 5 of the 10 doubles there 
reported were early ; this number, with the 13 singles so classed, makes 
a total of 18 early-type plants out of 30. The ratio is slightly nearer 
to 1 : 1 than to 3:1, and the former proportion would suggest the 
peculiar type of inheritance found with the mutant types yet to be 
described. The evidence of the 1910 distributions, however, shows that 
the early type largely predominates in the next generation witli both 
singles and doubles, and apparently this is true even when we exclude 
the progeny of the one parent classed as pure early. 

The early factor can be positively detected only by progeny tests. 
No test has shown the presence of this factor elsewhere than in WG9- 
ClO and part of its descendants. WG9-C10 produced the early and 
Snowflake types among 20 single progeny nearly in the typical mono- 
hybrid proportions. Inspection of the double progeny in two genera- 
tions suggests similar or possibly somewhat lower proportions there. 
A vicinistic origin for "WG9-C10 is improbable. Presumably, then, 
the early tj'pe arose from Snowflake by a single factor mutation, the 
dominant mutant factor being inherited without special complications. 
We shall now consider certain apparently mutant types which are 
characterized by peculiar genetic behavior. 

2. THE SMOOTH-LEAVED TYPE 

This type was first observed in the cultures of 1908 (table 1) and 
has occurred frequently in later cultures (table 3). It is perhaps the 
mutant type of most frequent occurrence among progeny of Snow- 
flake or early parents; 2410 unseleeted progeny from house-sown seed 
of such parents (see table 28) included 28 apparent mutants (14 
singles, 11 doubles, and 3 undetermined), a mutation coefficient of 
1.16 ± .15 per cent. 

As grown in the greenhouse at Ithaca, this type (fig. 7, tables 12 
and 13) was often many-noded, with correspondingly late flowering. 
Its most striking peculiarity, shown especially by young seedlings and 
not evident in the figures, was a lack of buckling between the veins 



[118] 



MUTATION IN MATTHIOLA 



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[1191 



262 MISCELLANEOVS STUDIES 

of the leaves, and of general convexity of the upper surface of the 
leaves. Mature plants developed under favorable conditions in the 
greenhouse closely resembled Snowflake; the leaves, however, were 
noticeably brittle, and the dry capsules so brittle that it was often 
necessary, as it was not with Snowflake, to shell the seeds individually. 
Probably the tibrovascular system is in some way defective; Oenothera 
rubrinervis, which is also brittle (de Vries, 1906, lecture 18), has 
thin-walled bast fibers. 

In the field cultures, both at Ithaca (fig. 5) and at Riverside, under 
conditions less favorable on the whole to the initiation of flowering, 
this tj'^pe (fig. 8) diifered much more widely from Snowflake. Flower- 
ing was excessively delayed, and the plants often remained low, with 
few branches, and rosette-like, with thin, rather narrow leaves. Small 
brown dead spots, possibly due to excessive transpiration, occurred so 
frequently on the leaves as to constitute a good diagno.stic character 
for the type. Another peculiarity observed in the field is a reflexed 
position of the tip of the j'oung leaf when first visible — Snowflake 
leaves being completely erect from the first. 

In the 1914 cultures, with better development than in other field 
cultures, some smooth-leaved plants (figs. 9 and 10) were again more 
like Snowflake, though later and evidently more leafy. 

Six smooth-leaved parents have been used in progeny tests, three 
of these being apparent mutants and three being Fj progeny of two 
of those mutants. The results are presented in tables 24 and 25 ; those 
tables require a brief explanation, which will apply also to the similar 
tables for other types. 

For the plan of the new pedigree numbers here used, see "^Methods. " 
The initial plants of a series are designated as the Pi generation in 
the tables, their progeny as Fi, ete. In table 24 the cultures are 
aiTanged according to their generations and their pedigree numbers 
under each generation; the smooth-leaved parents (P, or of the P, 
type) are given first, followed by the extracted Snowflake parents. 
In table 25 "good germination" indicates that in all lots included 
(taken as grown, not as summed by parents in table 24) the number 
of plants determined exceeds 50 per cent of the number of seeds sown. 
and vice versa; the weighted mean percentages obtained by dividing 
the total numbers of plants by the respective total numbers of seeds 
are given for each table in a footnote. 

All six smooth-leaved parents (tables 24 and 25) gave mixed 
progeny, part smooth-leaved and part Snowflake, The surprising 



[120] 



Mrr.iTioy in matthiol.i 



263 



fact is that the parental (smooth-leaved) type appears not in three- 
fourths of the progeny, but in only about one-fourth. 

The extracted Snowflake parents tested behave like pure recessives, 
showing no intluence of their smooth-leaved ancestry. Only the 
aberrant ratio seems inconsistent with the assumption that the smooth- 
leaved individuals tested were ordinary heterozygous dominants. 

The relatively weak growth of this type and the apparently poor 
germination of the seed produced by it suggast that normal segregation 
may be masked by selective elimination. Possibly the smooth-leaved 

T.A.BLE 2.5 

Smooth-leaved type: heredity. Summary. 





Progeny 




Cultures 


Seeds 


Plants 


Parents 


Total 


examined 


Smooth-leaved 




Undeter- 


Deter- 












mined 


mined 


Number 


Per cent 


All smooth- 














leaved 


Ithaca 


304, ;2/ 7 


7 


156 


40 


25.6 ± 2.4 


All smooth- 














leaved 


Riverside 


196 


1 


78 


23 (24) 


30.8 ± 3.4 


All smooth- 














leaved (6) 


All 


500,5/7 


8 


234 


63 (64) 


27.4 ± 2.0 


All P, smooth- 














leaved (3) 


All 


244, ?/r 


3 


115 


32 


27.8 ± 2.8 


All Fi smooth- 














leaved (.3) 


.\11 ■ 


2.56 


5 


119 


31 (32) 


26.9 ± 2.S 


All smooth- 


Germination 












leaved 


good 


293, 138 


8 


187" 


55 (.56) 


29.9 ± 2.2 


All smooth- 


Germination 












leaved 


poor 


207, 79 





47a 


8 


17.0 ± 4.4 


All Sno\vflake 














(5, Fi and F.) 


AH 


208, -50 


2 


173 









■ Respectively 63.8 and 22.7 per cent of the numbers of seeds planted. 

factor is lethal when homozygous, as is often the case (MuUer. 1918) 
with dominant mutant factors in Drosnph ila ; the data for germi- 
nation, however, indicate that two-thirds of the mature embryos can 
hardly belong to the mutant type. We might expect, in view of the 
weak growth of .smooth-leaved plants, that partial elimination of 
heterozygotes would also occur. That this is the case is suggested, 
though the numbers are small, by the lower proportion of the mutant 
type with poor germination (table 25; see also tables 39 and 40) ; it 
should be noted, however, that transferring the first lot of table 24, 
the only lot between 50 and 73 per cent, to the "poor" total, makes 
the percentages practically identical." 



'3 See also table 2 and the second paragraph under "Occurrence of Mutants." 



[121] 



264 MISCELLANEOUS STUDIES 

In connection with the qnestion of lethal action we must consider 
the inheritance of doubleness of flowers. Snowflake seed regularly 
gives a mixture of singles and doubles, about 53 per cent being doubles. 
The doubles, which are totally sterile, are probably (Frost, 1915) pure 
reeessives (dd) for a single-double factor pair. The singles are always 
heterozj'gous (Dd) ; crosses with pure single races fSaunders, 1911) 
show that the approximately 1 : 1 ratio and the failure to produce pure 
singles, with self pollination, are due to the fact that all the functional 
pollen is doubleness-carrying (d). The excess of doubles over 50 per 
cent has been explained by Miss Saunders (1911) as due to hetero- 
zygosis of the singles for two linked complementary factors necessary 
to singlenass, and by the present writer (Frost, 1915) as due to lower 
viability of the "single" gametes or embryos. The absence of func- 
tional single-carrying pollen is apparently due to a lethal factor acting 
after separation of the microspore tetrads, since the tetrads themselves 
appear normal. 

In any consideration of factors linked with the single-double pair, 
this semisterility of the pollen must be remembered. For example, 
any dominant factor completely coupled with D in pollen formation 
would be totally absent from the functional pollen, and the zygotes 
produced by selfing would show directly the .strength of linkage in the 
ovules. 

The available data for the smooth-leaved type (table 24) are far 
from con.stituting an adequate test of linkage, but they suggest that 
the factors are independent. Certainly no high degree of linkage is 
indicated by the totals, nor do the detailed data .suggest that smooth- 
leavedness is coupled with singleness in some parents and with double- 
ness in others. 

We must admit that the peculiar inheritance of this type is not 
yet positively explained. Evidently larger cultures are needed, and 
crossing with the Snowflake type and with other commercial varieties ; 
cytological .study may also be required. Certain comparisons and 
speculative possibilities deserve mention, however, especially since the 
types yet to be discussed furnish additional evidence bearing on them. 
We may compare the smooth-leaved and double types, as follows : 

DouBi.E Smooth-leaved 

1. A rare mutation of pure single 1. Apparently a common mutation 

("normal"). of pure Snowfliike ("normal"). 

2. Recessive; extracted reeessives 2. Apparently dominant; extracted 

are sterile mutant-type plants. reeessives are fertile normal 

plants. 



MUTATION IN MATTHIOLA 



2fi5 



Double 

3. Homozygous dominants not pro- 
duced by hybrids, because func- 
tional pollen carries recessive 
factor only. 

4. Eecessive (mutant) type the 

more vigorous. 



Dominant factor or another fac- 
tor very closely linked with it 
is incompatible with formation 
of functional pollen. 

Eecessive type exceeds the ex- 
pected equality by about 3 per 
cent among some 7000 indi- 
viduals. 



Smooth-leaved 
3. Homozygous dominants perhaps 
not produced by hybrids.'* 



4. Recessive (normal) tyjie the 
more vigorous; difference much 
greater than with single and 
double. 

.5. Relation of dominant factor to 
viability of pollen not yet de- 
termined. 

6. Eecessive type exceeds equality 
by about 23 per cent among 
234 individuals. 



The most probable hypothesis for .smooth-leavedness, theu, would so 
far seem to be essentially the same as for doubleness — complete elimina- 
tion of the weaker type in pollen formation, and partial elimination in 
embryo-sac formation. Reciprocal crosses with Snowflake are obviously 
necessary; as we shall soon see, three of the other mutant types have 
already proved to he carried by both eggs and sperms. 

The case of Oenothera lata (Gates, 1915) suggests the possibility 
that the smooth-leaved form might arise by reduplication of a chromo- 
some. With ordinary 0. lata the pollen is sterile, but pollination by 
0. lamarckiana gives about 15-20 per cent of lata. This deficiency of 
lata individuals is due, it seems, to a frequent loss of the extra 
chromosome at meiosis in lata ovules, with a resulting formation of 
more than 50 per cent of seven-chromosome {lamarckiana) eggs. 

If the smooth-leaved type originates through duplication of a 
chromosome, we might .suppose that other types of similar heredity 
involve other pairs of chromosomes. The apparent parallel with 
0. lata, which Bartlett (1917) has noted, was long ago suggested by 
the data, but with at least two or three types to be described linkage 
phenomena have seemed to conflict with this interpretation. Possibly 
different processes have produced different mutant types as with 
Oenothera ; as we have considered types siiggestive of 0. rubrinervis 
(early) and of 0. lata (smooth-leaved), we ma.v consider next a form 
which in appearance is remarkably suggestive of 0. gigas. 



'■• This possibility is only suggested by these cultures, but it becomes highly 
probable when the data for other types are considered. 



[ 123 I 



266 



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[124 1 



UVTAriOX IN MAirHIOLA 267 

It should, however, first be noted that, as will appear later, phe- 
nomena of apparent linkage in the ease of certain other types (erenate, 
slender, and narrow) suggest that these forms commonly arise from 
Snowflake by segregation rather than by immediate mutation. The 
obvious objection to this hypothesis is the fact that the apparently 
mutant types seem to be dominant to the ' ' normal ' ' or Snowflake type. 
This objection can be met by assuming the presence of dominant in- 
hibiting factors in the Snowflake parents that give apparent mutants.'"' 

If the apparent mutants of the smooth-leaved type are thus pro- 
duced by crossing over in a set of balanced factors, the lethal "balanc- 
ing" the smooth-leaved factor itself may be distinct from that which 
sterilizes the singleness-carrying pollen. In considering the results 
here reported, therefore, we must always bear in mind the possible 
presence of several unidentified lethal factors. If the apparent absence 
of linkage between the smooth and double factors is not misleading, we 
must suppose that these factors are carried by different pairs of 
chromosomes; considerations advanced by Muller (1918, pp. 479-482), 
however, make it rather probable that the commoner types of apparent 
mutants here discussed are all due to factors carried by one pair of 
chromosomes, the pair containing the factor for doubleness and its 
normal allelomorph. 

3. THE LARGE-LEAVED TYPE 

A double of this t.ype probably occurred in the 1907 cultures, 
though its appearance attracted so little attention that no record was 
made. In the field cultures of 1911 (table 3) several individuals sug- 
gested a gigas type, though there seemed to be intergradation with 
Snowflake. In the 1912 cultures a single with leaves "long, rather 
narrow, thick" developed normally and produced an abundance of 
good seed; from this individual f28a) all cultures of this type are 
descended. 

This type is stout and coarse throughout, and late to flower. The 
leaves are strikingly long, thick, and rigid, though as a rule relatively 



i-"" A letter suggesting this explanation was received from Dr. Muller soon 
after the same idea had been outlined in the "General Discussion" section below. 
Dr. Muller kindly gave further attention to difficulties at first encountered by 
the present writer, materially assisting in the formulation of an apparently 
tenable form of the hypothesis. Since, however, this scheme may seem "far- 
fetched" and unduly complex, it appears desirable to leave the original discus- 
sion of the individual types substantially unchanged. When the difficulties 
encountered by the assumption of frequent true mutation have been more fully 
presented, the need for some such addition to the scheme will be more evident. 



[1251 



268 



MISCELLANEOUS STUDIES 



narrow ; under unfavorable weather conditions the flowers are often few 
and defective, while the leaves are resistant and long-lived (fig. 11). 
Figures 12 and 13 show well the coarse leaves and lateness of well 
developed large-leaved plants in the 1915-16 cultures, the plants in 
the latter figure being several weeks the older. 

The results of the progeny tests are given in tables 26 and 27. All 
the twenty large-leaved individuals tested have given mixed progeny; 
the proportion of the mutant type, though much larger than with 

Table 27 
Large-leaved type: heredity. Summary. 





Progeny 




Cultures 


Seeds" 


Plants 


Parents 


Total examined 


Large-leaved 


















mined 


mined 


Number 


Per cent 


28a 


1013, 1914, 














& 1915-16 


122 


2 


73 


38 (40) 


54.8 ± 3.9 


28:i-F, (3) 


1914 


120 


2 


40 


14(19) 


47.5 ± 5.3 


28a-F, (12) 


1915-16 


288 


2 


190 


76 (90) 


47.4 ± 2.4 


28a-F2 (4) 


1915-16 


90 





54 


25 (26) 


48.1 ± 4.6 


28a-F, & F, (19) 


.\11 


498 


4 


284 


115(135) 


47.5 ± 2.0 


All large-leaved 














(20) 


.A.11 


620 


6 


357 


153 (175) 


49.0 ± 1.8 


Large-leaved 


Germination 














good 


360 


3 


260'> 


115(131) 


50.4 ± 2.1 


Large-leaved 


Germination 














])oor 


260 


3 


97" 


3S (44) 


45.4 =t 3.4 


Snowflake (1,F,) 


191.5-16 


24 





15 









■ Mainly from unguarded flowers; see table 26. 

" Respectively 72.2 and 37.3 per cent of the numbers of seeds planted. 

smooth-leaved, approximates to 50 per cent, not 75 per cent, with little 
indication of selective elimination with poor germination."' 

Here plainly, as with smooth-leaved, no pure mutant-type parent 
has yet been tested. Since this is also true of the other types, aside 
from early, that have been somewhat extensively tested, and fifty-three 
mutant-type parents in all have given Snowflake progeny, it is prob- 
able that homozygous individuals of these types seldom or never 
develop. The actual adult ratio with large-leaved is plainly not 2 : 1, 
but rather 1 : 1, a fact that would suggest absence of the mutant-type 
factor or factors from the pollen. The small trial cultures .started 
in 1917, however, show that the type is carried by both sperm and 
eggs. 



i« Since hybrids are of the mutant type in appearance, the possible cross 
pollination by Snowflake parents could hardly give Snowflake progeny with any 
pure large-leaved parent. It may, however, have reduced slightly the proportion 
of large-leaved progeny from heterozygous parents of this type. 



fl261 



MUTATION IN MATTHIOLA 



269 



If we are dealing here with a type cytologieally like Oenothera 
gigas, or rather the triploid semigigas, abnormal distributions of 
chromosomes may occur at meiosis, giving unpredictable genetic 
results. There has been special difficulty, as the numbers of doubtful 
individuals in table 26 suggest, in separating large-leaved from Snow- 
flake, though in part of the cases the diffei'ence is extreme. Possibly 
some of the doubtful individuals are genetic intermediates due to 
irregular meiosis in triploid nuclei ; such irregularities in division 
(Gates, 1915) occur with Oenothera. Both cytological examination 
and crosses with Snowflake are plainly required. 

Table 28 

Crenate-leaved type: numbers of apparent mutants and association of the 
type with singleness of flowers. 





Progeny of Snowflake and early parents 












Culture 


Total 
examinedi* 










Single 


Double 


All 


Coefficient of 
mutation 


1908 


725" 


6 


1 


7 


.97 =t .22 


1910 


338 


3 





3 


.89 ± .32 


191 IF, seed house- 












sown 


2072 


13 


3 


16 


.77 ± .13 


All above 


313.5 


22 


4 


26 


.83 ± .11 


All unsclected 


2410 


16 


3 


19 


.79 ± .12 



* See note 6 to table 2. 
■• See note c to table 1. 



4. THE CRENATE-LEAVED TYPE 

This type (tables 1 and 3) is one of the three aberrant types of 
most frequent occurrence in the cultures here described, having con- 
stituted (table 28) about .79 per cent of the progeny of Snowflake 
and early parents. A large majority of the individuals have been 
singles, as table 28 shows. If the apparent mutants are produced by 
some process of segregation of factors, evidently the crenate and single 
factors were usually coupled in this material; if they are produced 
by immediate factor mutation, or are individually due to some change 
in a particular locus, evidently that locus is linked with the single- 
double locus and the change is more frequent in the single-carrying 
chromosomes; and finally, if they are due to reduplication or loss of 
a chromosome, the apparent linkage remains to be explained. 

The margins of Snowflake leaves vai-y from entire or slightly 
sinuate to coarsely and irregularly dentate or serrate, this character- 
istic being subject to much environmental modification and varying 



270 



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[128) 



MUTATION IN MATTHIOLA 



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[129 1 



272 MISCELLANEOUS STUDIES 

with the position of the leaves on the plant. In the crenate-leaved 
type this character is much accentuated, as can be seen by comparing 
figure 14 witli figures 1 and 3 ; a warm greenhouse (fig. 14, upper line) 
gave very marked serration, while a cool greenhouse (lower plant, and 
also fig. 15) produced leaves much more nearly entire. 

Under the much more extreme conditions of insolation, temperature, 
and humidity at Riverside, this type was often much dwarfed in com- 
parison with Suowflake (figs. 16 and 17; see also fig. 23). In general, 
growtli is weaker than with Snowflake and the stems more slender. 
Buds and flowers are often produced in great abimdance, but the 
capsules are relatively few, small, and few-seeded. See tables 12 and 
13 for internode data. 

The progeny tests (table 29) show a slightly higher proportion of 
nuitant-type progeny than occurred with smooth-leaved. A striking 
new feature appears for the first time in these results, the regular 
presence of linkage, or an association sinndating linkage, with the 
single-double allelomorphs. Further, in all tlie four apparent mutants 
tested the erenate factor seems to be coupled with singleness, while 
among the sixteen F^ and F^ erenate parents there seem to be no 
crossovers.'" We seem to be justified, for reasons just given, in 
summing tli6 progeny as in the tables. Two things appear at once in 
table 29: (1) there is a great excess of total doubles over the usual 
53 per cent; (2) there is a much greater excess of doubles with Snow- 
flake than of singles with erenate; (3) the supposed double-recessive 
class (Snowflake double) is about two and one-half times as large as 
the double-dominant class (erenate single). 

Table 30 adds two features of special interest. First, there is good 
evidence of selective elimination with poor germination ; compare the 
remaining percentages with those for "Ithaca, field," "1915," "Pj," 
and "Germination poor," and see tables 39 and 40; the only excep- 
tional ease is the low percentage for the thirty plants of 1915-1(1. It 
would be surprising if the slow and weak growth of the erenate plants 
did not lead to such a result. Second, there is evidence that the 
erenate individuals are smaller than Snowflake even before germina- 
tion. The seeds of erenate i)arents are le.ss uniform in size than those 
of Snowflake parents; small seeds are numerous, and even the larger 
ones probably weigh decidedly less than normal Snowflake seeds. 
"With five erenate parents included in the cultures of 1913, random 



I' With four of the parents the tests are obviously entirely inadequate; one 
other, 22d-9, gives no indication of linkage among nineteen progeny. 



{i:w] 



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[1311 



274 



MISCELLANEOUS STUDIES 



samples of seed were sorted, and tlie smaller and larger seeds planted 
separately. 

Table 31 gives the data from this test. Here is practicallj' con- 
clusive evidence (.see tables 39 and 40) that the smaller seeds much 
more often contain embryos of the crenate type.^* Since the embryo 
of a Matthiola seed occupies practically all the space within the seed 
coats, it is evident that even as embryos Snowflake plants exceed 

Table 31 

Cultures of 1913. Crenaie-Jeaved type: proportions from smaller and larger 

seeds of crenate parents. 





Seeds 


Progeny 


Parent 


Total 
deter- 
mined 


r- * 1 A 


















Snowflake 


Other 




Size 


Number 


Number 


Per cent 


types 


22a-l 


Smaller 


21 


6 


4(5) 


83.3 ± 


12.9 





1 


22a-l 


Larger 


29 


23 


3 


13.0 ± 


6 6 


19 (20) 





22a-,') 


Smaller 


17 


11 


4 


36.4 =t 


9 5 


6 


1 


22a-5 


Larger 


.3.3 


28 


2 


7,1 ± 


6.0 


25 


1 


22b 


Smaller 


13 


8 


5 


62.5 ± 


11.2 


3 





22b 


Larger 


36 


31 


4 


12.9 ± 


5.7 


25 (27) 





22d-12 


Smaller 


30 


24 


17 


70.8 ± 


6.5 


5 


2 


22d-12 


Larger 


70 


57 


11(12) 


21 1 ± 


4 2 


42 (44) 


1 


22d-15 


Smaller 


32 


24 


17 


70.8 ± 


6.5 


3 


2(4) 


22d-15 


Larger 


68 


54 


18 


33.3 ± 


4.3 


34 (35) 


1 


AH 


Smaller 


113 


73" 


47 (48) 


65.8 ± 


3 7 


17 


6(8) 


AU 


Larger 


236 


193« 


38 (39) 


20.2 ± 


2 3 


145(151) 


3 


All 


All 


349 


266 


85 (87) 


32.7 ± 


19 


162(168) 


9(11) 



° Respectively 64.6 and 81.8 per cent of the numbers of seeds planted. 

crenate plants in size. This fact, obviousl.y, is further evidence in 
favor of the hypothesis of partial selective elimination of crenate 
heterozygotes during embryonic development. 

It may be worth noting that the 73 plants from the smaller seeds 
include 6 (8) apparent mutants of other types (mutation coefficient 
11.0 per cent), while the 193 plants from the larger seeds include 
only 3 apparent nuitants (1.6 per cent). 

Before we can profitably discuss these data further, we must con- 
sider the results from cross pollination (tables 32 and 33). The 
numbers, though small, make it very probable that both eggs and sperms 
carry the crenate factor. Further, it appears from series 20 that only 
a small portion of the sperms carry this factor, as we should expect 
from its apparent linkage with singleness. If homozygotes are non- 
viable, the combined crenate percentages of reciprocal crosses should 



IS The ])Oorer germination of the smaller seeds suggests that the disparity 
between the two lots of seeds in the proportion of crenate embryos was even 
greater than the cultures indicate. 



[132 



MUTATION IN UATTUIOLA 



275 



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[133] 



276 



MISCELLANEOUS STUDIES 



exceed the percentage from selfed parents ; the expected high pro- 
portion with series 21, however, might well be realized with adequate 
numbers and good germination. 

In spite of the small totals, it is very probable that linkage similar 
to that of the selfed cultures prevails with series 21. "Where the 
crenate type is the pollen parent (series 20) linkage ratios are on our 
hypothesis impossible, since the eggs are all Snowflake and the sperms 
all double ; the data, however, though statisticallj'' inconclusive, sug- 
gest that the excess of singles with crenate and of doubles with Snow- 
flake is greatly reduced but not abolished. 



Table 33 
Hybridisation of the Snoii-flal'e and crenate-leaved types. Summary. 





Progeny 




Cultures 


Seeds 


Plants 


Parents 


Total examined 


Crenate 




Undeter- 
mined 


Deter- 
mined 


Number 


Per cent 


20aa, bb, & cb 
20dc, ed, & ic 
20de,ff,gf,gg,&hd 
All of series 20 
21aa, bb, & dd 
Snowflake par- 
ents of hybrids 
(5) 


1913 
1914 
1915-16 

All 
All 

All 


123 
163 
120 
406 
75 

271,. 50 


5 


5 
1 

3 


93 
14 

103 

210 

25 

134 


5(6) 

6 

11(12) 
2(3) 

(1) 


6.5 =>= 1.6 


5.8 ± 1.5 

5.7 ± 1.1 

12.0 =*= 4.4 

.7 ± .5 



If we may ignore the doubtful correlation just mentioned a fairly 
adequate complete hypothesis for the selfing ratio is possible. Assume 
(1) a gametic ratio'" of 5DC -.IdC -.'iDc-.bdc, or 16% per cent of 
crossing over ; (2) non-viability of homozygous crenate (CC) ; (3) low 
viability of simplex crenate (C'c), eliminating an average of 60 per 
cent of this type; and (4) coupling of D and C in all parents tested. 
Evidence has already been prasented for assumptions (1), (2), and 
(3), except as to the intensity of linkage, while (4), as will be seen, 
is not at all improbable. 

Random fertilization under these conditions, excepting (3), would 
give 26DdCc (crenate single) -\- lOddCc (crenate double) + 5Ddcc 
(Snowflake single) -\- 25ddcc (Snowflake double). The other two 
clas.ses, 5DdCC and IddCC, would be non-viable pure crenate. Adding 
assumption (3) gives the following comparison: 



19 Representing the singleness ami doubleness factors by D and d, and the 
crenate factor and its "normal" allelomorph by C and c. 



[1341 



UVXATION IN MATTHWLA 277 

DdCc ddCc Ddcc ddcc 

, Theoretical ratio (« = 44.4) 10.4 i 5 25 

Calculated for n — 540 126 49 61 304 

Observed ()i = 540)» 125 51 57 307 

This fit surely caunot be criticised, whatever may be thought of 
the devices employed to obtain it ! With cross pollination the agree- 
ment is fairly good in the case of series 20, which gives the only fairly 
reliable data. We are assuming 16% per cent of crossover dC sperms: 
elimination of .60 of 16% per cent, or 10 per cent of the total, gives 
.06%/.90 = 7.4 per cent expected crenate, as against 5.9 per cent 
observed. Series 21 is supposed to have 50 per cent of C eggs in 
the ratio 7>DC AdC ; elimination of .60 of this proportion, or 30 per 
cent of the total, would leave .20/.70 = 28.6 per cent, against 12.0 
per cent in the very inadequate material observed. An adequate test 
of the hypothesis obviously requires large hybrid cultures, from 
vigorous seed sown under favorable conditions for germination. 

A scarcity of crossover crenate singles follows from the hypothesis ; 
they constitute only one twenty-sixth of the total number of viable 
crenate single progeny of crenate parents. No direct evidence indi- 
cating that the crenate and double factors are ever coupled in singles 
has yet been discovered. 

If the supposed crenate mutants are due to immediate factor muta- 
tion, however, it seems strange that the same locus is changed more 
readily in a singleness chromosome than in one carrying the doubleness 
factor, in a ratio similar to the linkage ratio of later generations. 
If the apparent mutants are really segregates from a balanced-lethal 
combination, the observed original coupling of crenate with single 
might be an accident of sampling involved in the original choice of 
material ; other initial parents might give the reverse coupling. 

5. THE SLENDER TYPE 

This type is comparativel.y rare as an apparent mutant from Snow- 
flake or early; the 3135 plants reported in table 28 gave only 4 (6) 
mutants (2 singles and 4 doubles, 2 of the latter perhaps Snowflake), 
a mutation coefficient not over .19 per cent. This type seems to occur 
more frequently among progeny of crenate. a tj'pe similar in some 



-" Omitting 29 plants classed as neither crenate nor Snowflake, which as 
probably non-crenate should perhaps be added to Snowflake, and also 64 plants 
(13 crenate and 51 Snowflake) with flower data incomplete. Complete data for 
the total of 633 plants would plainly give a somewhat poorer fit, but this could 
be improved by assuming a slightly greater elimination of Ccii zygotes. 



[13.S1 



278 



MISCELLANEOUS STUDIES 



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[1361 



MUTATION IN MATTHIOLA 279 

respects, and vice versa. Under favorable conditions this type may 
closely resemble Snowflake, but is decidedly more slender in stems, 
leaves, and pedicels. A characteristic drooping of flowers and branches 
is well shown by two plants in figure 18 ; the single is 25b of the 
tables. The progeny of 25b shown in figure 19 illustrate a variability 
of the "slender" characteristics which has suggested the presence of 
genetic differences among plants classed as slender. The leaves often 
resemble those of crenate more closely than do Snowflake leaves. 

In the fleld at Ithaca flowering was markedly earlier than with 
Snowflake, and the type seems to be earlier on the whole. The River- 
side conditions have commonly given a decided dwarfing as compared 
with Snowflake, though not to the extreme degree that this has occurred 
with crenate (figs. 20 and 21). 

The results of selfing tests are reported in tables 34 and 35. The 
distributions have the same general characteristics as with crenate, 
with some remarkable differences. The excess of doubles with Snow- 
flake is very much greater, the ratio being about 30 : 1 ; with slender, 
however, the excess of singles is slight in the grand total and perhaps 
significantly variable with different parents. 

Plant 25b-ll, the "extreme" individual of figure 19, appears to 
give a real excess of slender over Snowflake, and of double slender 
over single slender, though the numbers are much too small for cer- 
tainty. The two parents classed as "extreme" are (tables 39 and 40)^^ 
quite probably genetically different from the other slender parents. 
It should be noted that plant 25b-6-8-6, progeny of one of the parents 
described as "extreme," has also given a relatively high proportion of 
slender progeny. Perhaps the "extreme" form is heterozygous for a 
second slenderness factor similar to the original one. 

The percentages of mutant-type progeny are (table 39) much more 
variable than with smooth, large, or crenate, and (table 40) there is 
no good evidence of selective elimination ; both these facts may depend 
on genetic differences among the parents tested. 

The great niodifiability of the various types, including Snowflake, 
indicated by a comparison of, for instance, flgures 14, 15, and 16, 
greatly complicates the positive determination of types. In the cul- 
tures of 1911H and 1913, where crowing in flats or aphis injury in 
the field interfered with normal development of some plants, the im- 
pression was obtained that the slender type occurred in several grades 



21 In the calculation of the probability of simple sampling, f is taken as 3 
(the number of cultures), not 2 (the number of parents). 



[137] 



280 



MISCELLAKEOrS STVDIICS 



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[138 



MVTATIOS I.\ M.irrillOLA 28] 

probably unlike genetically. In the 1916 cultures, on the other hand, 
with better development, this type seemed substantially as uniform 
as the others. 

If we ignore these possible genetic differences and attempt to 
apply the scheme worked out for crenate, difficulties appear at once. 
First, the scarcity of Snowfiake singles would indicate much closer 
linkage than with crenate, while the relative abundance of slender 
doubles apparentl.y contradicts this supposition. Second, the in- 
adequate results from crossing with Snowflake (table 36) suggest 
that the sperms carry the supposedly crossover slender factor at least 
as often a.s do the eggs. While crenate as pollen parent gives results 
agreeing tolerably with the hypothesis, slender gives results differing 
from these in the wrong direction. 

No doubt, however, the disagreements can be over emphasized. Both 
crenate and slender as seed parent seem to give the expected relations 
between singles and doubles, and series 23 also does this with the 
Snowflake progeny. Oljviously tlie functional sperms and eggs of these 
mutant-type parents exhibit different ratios between types, and the 
peculiar results in other respects with slender may be related to the 
added complication suggested above. The astonishing feature of the 
data, of course, is the great excess of single slender over double slender 
in series 23 — an excess which suggests an actual significant excess of 
singles in the totals of all types given by this cross — while with selfed 
slender there is a great total deficiency of singles. We may at least 
feel confident that the modifications of the single-double ratio, with 
this type and with crenate, are due to lethal action which also affects 
the proportions of viable slender and crenate gametes or zygotes. 

If differential viability before germination is an important factor 
with these types, very probably it differs according as Snowflake or 
the mutant type is the seed parent, and according to the parental 
environment. In other words, partial selective elimination during 
seed formation maj' vary with the environment of the embryos, accord- 
ing as this environment is affected by either the genetic constitution 
or the external environment of the seed parent. Until such uncer- 
tainties are eliminated, we are hardly justified in ruling out, for 
the types discussed, the probability that regular segregation and (in 
the last two cases) true linkage are concerned in these phenomena. In 
fact, the definite differences in ratios between reciprocal crosses and 
between at least one of the crosses and selfing encourage further 
attempts at satisfactory factorial analysis. 



[1391 



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MISCELLANEOUS STUDIES 



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I UOI 



MVTATION IN MATTHIOLA 



283 



6. THE NARROW-LEAVED TYPE 

As table 37 indicates, this type competes with crenate for second 
place in frequency of occurrence in the Ithaca cultures ; in fact, when 
only the strictly unseleeted cultures are considered the percentage is 
very close to that for smooth-leaved. A feature of special interest is 
the apparent association of the mutant type with doubleness. 

In a cool greenhouse this type (fig. 22) varied from exceptionally 
late and many-noded to ordinary in both characters. The leaves (see 
also fig. 18) were typically narrow, rather strictly entire, often rolled 
backward or twisted, and typically more ascending than those of 

Table 37 

Narrow-leaved type. Numbers of apparent mutants and association of Hie type 

with doubleness of flowers. 





Progeny of Snowflake and early parents 


Culture 


Total 
examined" 


Narrow-leaved 




Single 


Double 


All 


Coeffii'ient of 
mutation 


1908 

1910 

191 IF, house-sown 

Al'. above 

All unselectnd 


725" 

338 

2072 

3135 

2410 




1 

7 
8 
8 


2 
4 

12 
IS 
16 


2 

6 

20 

28 

26 


.28 ± .26 

1.78 ± ..38 

.97 ± .15 

.89 ± .12 

1.08 ± .14 



■ See note 6 to table 2. 
■• See note c to table 1. 



Snowflake. The apex of the leaf is often more acute than w'ith Snow- 
flake, and many leaves are mucronate or at least end in a sharp, rigid 
tip. 

A striking characteristic is the narrowness of the sepals, resulting 
in frequent early separation at the edges, partially exposing the petals 
in immature buds. 

Under the less favorable field conditions the plants often remain 
long as dwarf rosettes, and flower late and feebly if at all. Figures 23 
and 24 show comparatively well developed plants in the field. 

The type is on the whole very distinct in the field, though there 
has been some question whether a greenhouse plant such as that in 
figure 18 is genetically different from those with short and rigid 
leaves (figs. 22 and 24) ; the very great variability in leaf form due 
to external conditions makes such a question very difficult without 
extensive progeny tests. It is now (1918) probable that narrow-dark 
(p. 143) was not distinguislied from narrow in the greenhouse. 



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ri42! 



MITATIOX IX MATTUIOLA 285 

The few singles have produced few seeds, and these were higldy 
variable in size. The capsule often has a defective septum, more or less 
of the distal portion being absent. Germination was poor in the small 
cultures secured (table 38, upper part), with only 10.8 per cent of the 
mutant type among the progeny. 

This case agrees in most respects with those previously discussed, 
but adds one point of interest in the occurrence of apparent coupling 
of mutant type with doubleness rather than singleness. Seed appears 
to be less abundant and less well developed than with any of the pre- 
ceding mutant types, facts probably significant in relation to the low 
percentage of narrow progeny from narrow parents, though the large 
probable error of the percentage must be considered. 

7. MISCELLANEOUS ABERRANT TYPES 

As part of the aberrant individuals occurring in the greenhouse 
were either doubles or singles that produced no seed, while practically 
no seed was produced by any plants in the field at Ithaca or by even 
.some of the commoner mutant types at Riverside, the opportunity for 
progeny tests has been almo.st entirely limited to the types so far 
discussed. 

The narrow-dark-leaved type (table 3) was common and distinct 
in the field at Ithaca, where it constituted about .48 per cent of the 
2072 plants from house-sown seed, and has been readily identified 
in several cas&s at Riverside. It was not distinguished in the green- 
house cultures, but was very probably included under narrow-leaved. 
Possibly a single described as "small-convex-leaved" belonged to this 
type, though two field plants were given this name as distinct from 
narrow-dark; according to a photograph (fig. 25, second plant from 
left), another greenhouse plant (a double) may have been similar to 
narrow-dark-leaved. The narrow-dark-leaved type (figs. 26 and 27) 
has narrow dark-green leaves, strongly convex upward, and evidently 
tends to compactness of growth and lateness of flowering ; under field 
conditions it seems decidedly more like Snowflake than like narrow- 
leaved. 

The 44 progeny (table 38) secured from the greenhovise single 
mentionad above included 2 (4) narrow-dark-leaved individuals and 
3 (5) other plants not Snowflake (the last including two smooth, one 
large, one slender, and one .semicrenate), besides five undetermined 
plants. Plainly the type of the parent is still in doubt. 



ri43] 



286 MISCELLANEOUS STUDIES 

Another very different greenhouse plant, described as "stout 
dwarf" (fig. 25, third from left), gave among 29 progeny (table 38) 
5 (7) individuals evidently not Snowfiake, which may have been 
narrow-dark or may have belonged to another type tliat was somewhat 
similar under the conditions of the tests. The parent resembled 
Snowflake except in its short interuodes and short, stout capsules. 

Four other plants suspected of mutation apparently entirely failed 
to repeat their type in their progeny, perhaps because of the smallness 
of the house cultures. One of these was the plant, much branched 
for the warm greenhouse, third fi'om the riglit in figure 18; another 
was a very late plant with a remarkably large number of main-stem 
leaves ; the others were a plant with unusually small flowers and one 
with some of the leaves somewhat spatulate. Possiblj- all of these were 
Snowflake, though the second, which gave poor germination, probably 
was not. All these four plants have been included as Snowflake 
parents for tables showing numbers of apparent mutants. 

The small-smooth-leaved type is well shown in figure 25 (first and 
fifth from the left). It is the smallest and weakest of the fairly common 
and definitely identified types ; it has small, very smooth leaves, and is 
late in blooming. The two plants .shown were both singles, but they 
set no seed. 

The semicrenate-leaved type (table 3) differed slightly but appar- 
ently definitely from Snowflake, somewhat resembling crenate-leaved 
in leaf form. The one "pointed-erenate-leaved" plant of table 3 may 
have been crenate-leaved. The "compact" and "curly-leaved" plants 
of this table have not been identified with any aberrant types in other 
cultures. "With the remaining six types of table 3 all the individuals 
have been questioned as possibly Snowflake; it is now practically cer- 
tain that some of those in the second, third, and fourth groups 
belonged to the large-leaved type since studied, but the apparent inter- 
gradation with Snowflake makes any attempt at a definite reclassi- 
fication from the records a matter of doubtful value. 

The second plant from the right in figure 25 was remarkable for 
its short stem and few but large leaves. Several other more or less 
exceptional individuals have appeared in the cultures, especially among 
some plants with abnormal cotyledons, selected from large numbers of 
greenhouse seedlings in the 1908 cultures, which were examined for 
syncotyledony. Some of these were very weak plants which finally 
died without flowering. 



F144] 



MUTATJOX I.\ MATTlllULA 287 

The fluctuations in habit, leaf form, etc.. within the type are such 
that the determination of familiar types is often a matter of some 
uncertainty, as is shown b.y data that have been presented. It may 
well be that among the doubtful types are included several definite but 
comparative rare mutant forms, which occurred too infrequently to 
afford adequate material for positive classification. 



8. SOME PEOBABILITES OF RANDOM SAMPLING 

For compactness of presentation and convenience of comparison 
the material in tables 39 and 40, to which some incidental references 
have already been made, is collected here rather than scattered through 
the discussions of the various types, concerned. Some statements as 
to methods are also necessary in connection with each of the topics 
here treated. 

First, it should be noted that the percentages previously given 
have regularity been accompanied by the probable errors of simple 
sampling. These probable errors have been calculated by the formula 

E per cent = .6744898 y HH . wlicrc p is the percentage of the mutant 

n 
type ("successes"), q is 1 — p, and // is the size of the sample (the 

number of plants concerned). 

In the heredity tables for each type, p has uniformly been taken 
as the percentage of the total of the lots compared, or p^. 

For the "mutation coefficient" the percentage of the grand total 
of unselected house-sown lots has regularly been used. Evidently the 
few .selected progeny included in tables 1, 28. and 37 shovild be omitted. 
All the percentages here are so low that the probable errors deserve 
little confidence, even though n is usually fairly large. The rather 
close agreement of the percentages of all apparent mutants in the 
three distinct lots of unselected house-sown cultures suggests that 
they represent fairly well the population value for the potentialities 
of the seeds; and even if the mean percentage of the total of the lots 
for the main comparisons is actually nearer, it is safer to use the 
larger probable errors resulting from the method here employed. 
Furthermore strict use of p„ would sometimes require several slightly 
different probable errors for the same percentage, for use in different 
comparisons in the same table. 



[145] 



288 MISCELLANEOUS STUDIES 

If the probable error of the difference of any two percentages in 
the same table is to be obtained, therefore, formulae corresponding to 
those given by Yule (1911, pp. 26-1—267) are applicable. 

Now, it is possible in some of these cases to calculate the actual 
standard deviation of the percentage in subsamples which make up 
an aggregate sample. Table 39 givas such actual standard deviations, 
in comparison with the corresponding theoretical or expected standard 

deviations given bv , 

, = W PI 

" per cent ^^^^ • 

>i — 3 
Table 39 
Standard deviations of percentages of mutant types. Values derived from 



'PI, 



compared xoith values expressing the actual 


variability of subso 


mples. 






N 


/ 


n 


p 


Standard deviation of samples 


if mean size n 


Type of parent and grouping of 
progeny 


Actual 


Theoretical,.* 


PQ 
n-3 


Difference 
E<r 


Smooth-leaved type: 
All lots by parentage 
AH lot.s as grown 

Germination good 


234 
234 

187 


6 

12 

7 


39.0 
19 5 

26.7 


27.35 
27.35 

29.95 


7.5 
11 3 

10 9 


7.4 ± 
11.0 ± 
j 9.4 =t 
1 9.2" 


14 

1,5 
1.7 


+ ,1 
-f- .2 
-1- .9 


Germination poor 


47 


5 


9.4 


17.02 


5.2 


fl4.9 ± 

\17.6 


3.2 


- 3.0 


Large-leaved type: 
All lots by parentage 
All lots as grown 

Germination good 


357 
357 

260 


20 
22 

14 


17.85 
16.2 

18.6 


49.02 
49.02 

50.38 


10.7 
10 9 

11.3 


13 ± 
13.7 ± 

f 12.7 ± 
112. 7 


1.4 
1.4 
1.6 


- 16 

- 2.0 

- .9 


Germination poor 


97 


8 


12.1 


45.36 


8.7 


/16.5 =>= 
116.6 


2.8 


- 2.8 


Crenate-leaved type: 
All lots by parentage 
All lots as grown 

Germination good 


633 
633 

549 


20 

28 

20 


31.65 
22.6 

27.45 


29.86 
29.86 

32.42 


10.6 
12.5 

10.7 


8.6 ± 
10.3 =t 
j 9.5 ± 
\ 9.3 


.9 

.9 

1.0 


-1- 2.2 
+ 2.4 
+ 1.2 


Germination poor 


84 


8 


10.5 


13.10 


10.5 


f 12.3 ± 
116.7 


2.1 


- .9 


Seed-size test, smaller seeds 


73 


5 


14.6 


65.75 


13.2 


(13.9 ± 
\13 8 


3.0 


- .2 


Same, larger seeds 


193 


5 


38.6 


20.21 


9 4 


( 6.7 ± 
I 7.9 


14 


+ 1.9 


Same, all seeds, by p.arentage 
Same, all seeds, as grown 
Slender type: 

All lots by ijarentage 
All lots as grown 


266 
266 

243 
243 


5 
10 

8 
13 


53.2 
26.6 

30.4 

18.7 


32.71 
32.71 

32.51 
32.51 


10.3 
22.9 

17.5 
19.7 


6.6 =t 

9.7 ± 

9.0 ± 
11.8 ± 


1.4 
1.5 

1.5 
1.6 


-1- 2.6 

-1- 8.8 

-1- 5.7 
-1- 4.9 


Germination good 


165 


7 


23.6 


33.33 


14.9 


I 10.4 ± 
1 10.3 


1.9 


+ 2.4 


Germination poor 


78 


6 


13 


30.77 


27.2 


j 14,6 ± 
114.8 


2.8 


-1- 4.5 


Parents ' ' extreme 


38 


3 


12 7 


63 16 


14 4 


( 15.5 ± 
1 15.1 


4.3 


- .3 


Parents "ordinary" 


205 


10 


20.5 


26.83 


14.7 


( 10.6 ± 
111.2 


16 


-f 2.6 


Narrow-leaved type: 
All lots as grown 


37 


3 


12.3 


10 81 


8.1 


10.2 ± 


2.8 


- .75 



' The sei'ond values for some cases in this coliimii are derived from p„ (see text). 



[14fil 



MUTATION IN MATTHIOLA 289 

For example, table 27 gives the percentage of large-leaved plants 
among the 357 progeny of the 20 large-leaved parents as 49.0 ± 1.8 

per cent. This probable error is given by .674-1898 \ — , where 

p = 49.0 per cent, g=;51.0 per cent, and w= 357. These 357 
progeny, as table 39 indicates, came from 20 parents which contribnted 
an average of 17.85 progeny each, and the actual standard deviation 
of the percentage in tiicse 20 sibships was 10.7 per cent. 

Obviously the expected standard deviation of simple sampling for 
comparison must represent samples not of 357 plants each but of 17.85 
plants each. Now a percentage is obviously a mean (of values all 
either or 1). Since "Student" (1908) has shown that the theoretical 
.standard deviation of the mean in samples is given more exactly by 

O" variate ,i i 0"variate 

than by a mean = 



Vw — 3 \'n 

(the value for the normal curve conventionally used for the probable 
error of the mean) and since '71, the mean size of sample, is small 
enough to make the correction a matter of considerable importance. 

V M — 3 is here used. Since o-variate^ VP9- we have (Tmean = 

V PI where «= 17.85. Thi.s gives a theoretical standard devia- 
'ot — 3 

tion of 13.0 per cent.-- 

It is true (Yule, 19n, p. 260) that the ordinary method of calcu- 
lation of the actual standard deviation is not satisfactory for means 
when the samples vary in size. A method has been used, however, which 
obviates this difficulty, so that comparison with the results given by 

is strictly legitimate. Each squared percentage deviation 



i 



« — 3 
ha.s been weighted by multiplying it by the number of individual 

plants which it represents, and the summation of squared deviations 

has then been divided, not by 2/, the number of samples, but by 

2/ X «. the number of samples multiplied by the mean weight or 

average size of sample (in other words, by N, the total number of 

individuals).-' 



-- In tlie calculations for table .SO p has been taken as the percentage fjiven 
in this table, to two flecimal places, while with all other numbers employed in 
calculation, including n — 3, three or more decimal places have been used as 
needed. 

-■■! Algebraic proof of the correctness of the method has kindly been furnished 
by Frank L. Griffin, Professor of Mathematics, Reed College, Portland, Oregon. 
If it develops that this rather obvious device has not been suggested for the 
purpose, it is to be i)resented elsewhere with the mathematical proof. When the 
variates are not grouped in classes the calculation is substantially as easy as 
without weighting, while the theoretical value is found with much less work 
than by the method given by Yule (1911, p. 260), which requires the harmonic 
mean of the sample sizes. 

11471 



290 



MISCELLANEOUS STUDIES 



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[1481 



MlTA'nUX IX MATTHIOLA 291 

In the calculation the deviations are taken from zero, and with 
these small numbers of samples the percentages are not thrown into 
classes; it si^fficos, then, to S(]nare eacli number of "successes," divide 
by the corresponding total of individuals, add the quotients, and 
divide by the grand total of individuals, correcting this weighted 
mean squared deviation by .subtracting the square of the weighted 
mean percentage (percentage of grand total). If s is the number 
of successes and n is the total number of individuals in the sub- 

sample, and M is the weighted mean percentage, then .1/=: — , and 

_ \~yl 

"■percent ^—t 11 -.„ 

Table 39 gives, for the most important comparisons of heredity 
percentages, the total number of progeny (yV)> the number of cidtural 
groups or (with the first line for each type) the number of parents (/), 
the average size of the groups of progeny (w), and the mean per- 
centage of the mutant type (p). This serves as a summary of some 
of the most important statistical data already presented relating to 
the inheritance of these types, and also shows the basis of the remain- 
ing part of this table and of table 40. For comparison of actual and 
theoretical standard deviations the theoretical value has been calculated 
from the actual percentage as given in this table. For comparison of 
means (table 40) the percentage of the corresponding total (p„) has 
also been used, this theoretical standard deviation being the second in 
the table in the cases where the two values are not identical. 

Since small changes in a percentage have little effect on its 
theoretical standard deviation, we are fairly well justified in taking 
the latter, as calculated from the actual percentage in each ease, to be 
the "population" value. Consequently, the difference between the 
theoretical and actual standard deviations has been expressed in each 
ca,se as a multiple of the probable error of the theoretical value. 

Aside from the last line for crenate-leaved, where there is an 
obvious artificial reason for high variability, there is no very significant 
difference except with slender. In this case, the deviation of 5.7 times 
the probable error (line 1) is probably largely due to the genetic 
differentiation of "extreme" and "ordinary" parents suggested by 
their appearance and by the wide difference in the heredity per- 
centages ; the differences become moderate when the progeny of the 
two classes of parents are .separated. 



(1491 



292 MISCELLANEOUS STUDIES 

In the two cases (smooth-leaved and crenate-leaved types) where 
the percentages of mutant types differ greatly with good and poor 
germination, separation according to germination gives a mean value 
of the standard deviation decidedly lower than the value for all lots 
taken together. In the case of the large-leaved type there is little 
change, while the considerable reduction with the slender type is 
probably due to unequal separation of lots from parents genetically 
different. 

Table 40 shows the simple-sampling probability of the most striking 
differences of heredity percentages, aside from the characteristic 
differences between different types. "Student's" (1917) table of 
pr()])abilities of mean deviations with small samples is used, with 
interpolation by second differences. Where the standard deviation 
of the difference is required it is found from the theoretical values 
given in table 39 by the formula (Yule, 1911, pp. 264-265) 



C difference V "^l ~l~ O'; 



J Pogo 



Po g« 



ji, — 3 «2 — 3 

when one statistical population is assumed (table 40, columns 2 and 3). 
When two popiilations are assumed (table 40, columns 4 and 5) the cor- 
responding formula using p,i7, and p„q., is employed. In the one case 
where this is possible (the seed-size test), it is also calculated from the 
actual differences of the pairs of percentages in the separate tests, each 
difference being weighted with the total number of progeny from the 
parent concerned. Where two values of / (the n of "Student's" 
table) are involved, the smaller is taken, giving understatements of the 
probabilities involved ; in the two cases where the difference is more 
than 2. the values are recalculated, with / as the nearest smaller 
integer to the geometric mean of the two actual numbers (that is 
with /o= V/i/2)- In the ca.se where the probabilities of four devia- 
tions all in the same direction are combined, the four chances of 
occurrence are nuiltiplied together; that is, if the i(l-|-a) of 
"Student's" table is P, and 1 — P is F, then F,.„.,.^ = F,-F„-F^-F,. 
"Student" (1908, p. 1) says, "The usual method of determining 
the probability that the mean of the population lies within a given 
distance of the mean of the sample, is to assume a normal distribution 
about the mean of the sample . . . ." AVhen this is done with a differ- 
ence of means, it is at once evident that only half of the chances of 
deviations as great as the distance of the given difference from zero 
difference lie below zero difference: the other half of the chances of 



(isoi 



MUTATION IN MATTUWLA 293 

such deviations lie in the opposite direction and represent positive 
differences still greater than the sample difference. In other words, 
it' the implications of a sample difference are to be given full weight, 
thi.s dift'erence must be considered the most probable value of tlie 
theoretical "true" difference between two assumed distinct statistical 
populations. In the present case we wish to know the probability that 
the "'true'' or theoretical-population means differ in tlie same sense 
as the observed sample means. This involves calculation of the proba- 
bility of deviations in one direction (beyond zero difference) from 
the .sample difference. If the sample difference of means is considered 
as positive, then the negative "tail" of the theoretical frequency 
curve of sample differences (this curve being centered at the observed 
sample difference) must be compared with the rest of the curve. The 
positive portion of the curve the i (1 -(- o)-* of the tables, then gives 
the chances favoring the hypothesis that the sample means truly 
represent the population means. The odds in favor of the hypothesis 
are therefore given by the formula 

Values calculated from this fornnila are given in columns 4 and 5 of 
table 40. 

When other considerations than the sample evidence are to be taken 
as determining the most probable value of the "true" mean, the case 
is different. For example, if the probability that our sample per- 
centages are mere sampling deviations from some theoretical Mendelian 
value were in question, that theoretical value mu.st be taken as the 
population mean and only the magnitude of the deviations must be 
considered. 

When a difference of means is considered from this latter stand- 
I)oint, it is assumed that the two samples come from one statistical 
population, and hence that zero is the most probable value of the 
population difference. If we choose to assume tliat the most probable 
value of the population difference in our eases is zero, we must 
calculate the odds against a deviation of the observed amount in 
either direction from zero difference. The formula for these odds is 

„ ^ (l+„)_^ (l_a) 

U, = „ ~ : or -L . 



2X^ (1— a) 



-■i Tlie whole area of the frequency eurve is taken as unity, and a is the area 
enclosed by any given deviation in both directions from the mean. 



[1.511 



294 MISCELLANEOUS STUDIES 

Values from this formula are given in columns 2 and 3 of table 40 ; 
their magnitude in three eases, however, and the uniform agreement 
of the direction of difference with the exjiectation from biological 
evidence which has been discussed, weigh heavily in each test against 
the assumption of random sampling from a single statistical population. 

It does not appear necessary, however, thus to weigh the evidence 
in detail before deciding which formula is suited to the ease. There 
is no evident theoretical value from which these percentages are 
reasouablj' likely to be sampling deviations. This being the case, and 
granting such general possibilities as that of differential viability, it 
seems most reasonable to use the former (Oj) formula. That is, we 
.should give full weight to tln' implications of a sample deviation 
luiless there is some definite reason for assuming that some other value 
better represents the mean of the theoretical statistical population. 

It must be remembered that the actual probabilities of sampling 
deviations do not necessarily correspond closely with the probabilities 
of random sampling. With the material in table 40, however, aside 
from the germination comparison in the case of the slender type, 
table 89 suggests a fair agreement with the conditions of random 
sampling. The actual standard deviations of the subsamples do not 
in general differ widely from the corresponding theoretical values, and 
the differences are negative about as often as positive. 

The hypothe.sis of selective elimination with poor germination is 
strongly .sustained (table 40), although only one difference (with the 
crenate type) has much statistical signiticance when considered alone. 
If we may multiply together the members of the four ratios in column 
3 of the table, the combined odds (using the /„ values) are 130:1 
against occurrence of these four deviations as accidents of simple 
sampling, when magnitude of deviation alone is considered. If 
direction of deviation alone is considered the random chance of these 
four deviations all in the same direction is obviously (^)*, or the odds 
favoring the elimination hypothesis are 15:1. Combination of these 
two chances indicates a high probability for the hypothesis. When 
the two-population formula is used in calculating the standard devia- 
tion of the difference (columns 4 and 5) the value of P is consider- 
ably reduced in some cases, and the combined odds obtained from 
F.^- F.,--F^-Ft are very high. Evidently the best single expression 
of the simple-sampling odds, though possibly somewhat too high, is the 
value given last in column 5. or 123,093:1. 

With the seed-size test of crenate the odds are 499 : 1 with the 
theoretical standard deviation of the difference, or 1666:1 with the 

[152] 



Mrr.iTioN IN iiArriiioLA 295 

actual standard deviation. When the relatively small size and weak 
growth of erenate seedlings are also taken into account, the relativel.y 
small average size of erenate embryos may be considered to be 
demonstrated beyond reasonable doitbt. 

With "extreme" and "ordinary" slender parents the odds de- 
cidedly favor the hypothesis of genetic differentiation of parents, in 
spite of the small numbers involved. We must remember that definite 
statistical differentiation of lots of progeny grown under uniform con- 
ditions does not necessarily demonstrate genetic differences (differences 
in output of gametes) between the parents; in this case, however, the 
difference in the appearance of the parents and in the single-double 
ratio among the progeny also suggest genetic differentiation. 



GENERAL DISCUSSION-' 

It might be argued with some plausibility that the available 
evidence hardly justifies conventional factorial analysis, or at least that 
the data indicate strongly the presence of marked factorial incon- 
stancy. The aberrant types occur in very small proportions among 
the progeny of selfed Snowflake parents, in much larger proportions 
from "mutant-type" parents, and in intermediate proportions from 
crosses with Snowflake. It might be supposed that the Snowflake type 
has a slight tendency to nuitate to the other types, and that these have 
a much more marked tendency to mutate back to Snowflake. Varioiis 
considerations, however, especially the occurrence of apparently 
regular linkage phenomena, seem to favor the general form of 
hypothesis which has been presented. 

As we have seen, it is well known from the behavior of various 
factors that the typical Mendelian mechanism is present in Maiihinla. 
It cannot be argued here, as sometimes with Oenothera, that the 
genetic behavior of the genus or species is fundamentally non- 
Mendelian. Since the Mendelian mechanism is demonstrably present, 
and [Muller's (1918) work on beaded wings in Drosophila seems to 
establish the adequacy of this mechanism in a closely parallel case, 
surely conventional factorial analysis .should be carried as far as pos- 
sible; in fact (iMuller. 1918, p. 423), a Mendelian explanation should 
not be abandoned for anything .short of positively contradictory 
evidence. 



2jMuIler's (1918) complete report on the beailed-wing case in Drosophila 
appeared several months after the present paper had gone to the publisher. 
Certain conclusions given below, very similar to Muller 's but not credited to 
him, were therefore reached independently. 

f 1.531 



296 MISCELLANEOUS STUDIES 

In the Drosophila case just mentioned, the " principal'' factor for 
the character in question is "dominant for its visible effect and 
recessive for a lethal effect," so that no pure beaded individuals 
appear among the progeny of beaded. The original race regularly 
gave progeny partly heterozygous beaded and partly homozygous 
normal, while after a long period of selection 4 true-breeding beaded 
race appeared. This latter form, it proved, fails to give normals not 
because of being duplex for beaded — it is still simplex — but because 
of its possession of another factor, known only by its lethal effect 
when homozygous, which is carried by the chromosome bearing the 
normal allelomorph of the factor for beaded. The locus of this reces- 
sive lethal factor gives in general about 10 per cent of crossovers with 
the locus of beaded, but in this case, because of the presence of a factor 
"which almost entirely prevents crassing over" between the loci of 
the two lethal factors, viable non-beaded zygotes are very rarely 
produced. Thus every zygote receiving either two beaded-carrying 
chromosomes or two non-beaded-carrying chromosomes of the pair 
concerned fails to develop, and all the insects produced are necessarily 
heterozygous for both lethal factors. 

A point of special interest in this ca,se is the fact that by certain 
crosses individuals can be produced which give certain types among 
their progeny in very small percentages. MuUer suggests that part 
at least of the supposed mutants of Oenothera may be due to crossing 
over between chromosomes carrying lethal factors, by which certain 
recessive factors are permitted to come to expression in viable zygotes. 

For the inheritance of doubleness of flowers in Matthiola he gives 
a "balanced-factor" explanation essentially identical with mine (Frost, 
1915). 

There seems to be little reason to doubt that the differential factors 
for these aberrant Matthiola types have originated by mutation. On 
the analogy of Drosophila we might expect that the true mutations 
woiild be relatively rare, and that most of the apparent mutants, in 
cases where they appear frequently, would be due to segregation, 
appearing as the result of crossing over in chromo.somes carrying 
balanced lethal factors. The evidence seems to indicate, however, that 
the differential factors for the mutant types at all extensively studied 
are dominant for their visible effects and usually (probably imper- 
fectly) recessive for a lethal effect, the mutant factors thus being 
genetically similar to the factor for beaded wings in Drosophila. 
This would seem to imply the occurrence of certain mutations in pro- 



ri54i 



MUTATION IN MATTHWLA 297 

portions as high as about 1 per cent, and a general mutation coefficient 
of perhaps 4.5 per cent, wliile the only jNIendelian alternative would 
seem to be some more complex scheme whose satisfactory formulation 
might require much more extensive hybridization data. 

To be more specific: (1) these types are not single reeessives, since 
they are not homozygous but split into the mutant and "normal" 
types; (2) they are not simple eases of multiple reeessives, as has 
been proposed by Ileribert-Nilsson (1915) for Oenothera mutations, 
since what is on that hypothesis the full dominant type reappears with 
selling; (3) if these types are single dominants, as they appear to be, 
they cannot (barring the action of inhibiting factors) arise from the 
pure recessive "normal" or Snowfiake type by segregation, but only 
by immediate mutation ; (4) they are not simple cases of comple- 
mentary dominant factors, since they occur among the progeny of 
selfed parents. 

"We might assume that a "mutant" type depends on two pairs of 
factors, one homozygous and the other heterozygous, while both pairs 
are heterozygous iu the "mutating" Snowflake parent. Thus the 

crenate tvpe might have the zygotic formula —, -r , where d is the 

d ci 

factor for double flowers, (' a dominant factor for crenate, and I a 

dominant inhibitor of C, all three loci being situated in the same 

eliromosome, at distances of, say, 16 and 4 units apart, in the order 

indicated. A Snowflake parent producing crenate progeny would 

then be^; — - or ., ' , aud crossover combinations would produce the 
dci del 

apparently mutant crenate progeny. The crenate progeny would 

behave as heterozygous dominants when selfed, and if CC zygotes 

were non-viable would yield constant Snowflake and inconstant 

crenate ; the extracted Snowflake singles, having the composition 

Dci 

— r^, could not throw crenate individuals except bv true mutation of 
del 

c to C. "With selfed Snowflake, if we assume 16 per cent and 4 per 
cent of crossing over in the two positions, and a 60-per-cent selective 
elimination of crenate zygotes, all CC zygotes being non-viable, sub- 
stantially the observed percentages of crenate singles and doubles 
result.^" 



2" See page 125, footnote. This scheme agrees fairly "nell with the results 
from crossing, and gives almost exactly the observed proportion of total doubles 
(a little over 53 per cent) for selfed Snowflake. Its adequate presentation must 
be reserved for a later paper. 



[155] 



298 MISCELLANEOUS STUDIES 

Formerly (Frost, 1916) the hypothesis of frequent dominant 
mntations seemed the more probable, but there is apparently non- 
conformable evidence. It is true that the peculiar behavior of the 
slender type might conceivably depend on an occasional mutation in 
another locus, or an exchange (Shull, 1014) or duplication of loci. 
giving two similar or identical factors for slender. An apparently 
fatal objection, however, is the fact that the supposed mutants seem 
to show linkage with singleness or doubleness at their origin from 
Snowflake as well as in subsequent generations — a fact which strongly 
suggests segregation in the former case. 

If the apparent mutants are really due to segregation complicated 
by lethal action, the origin of the complex heterozygosis indicated for 
Snowflake is doubtful ; it may be due to hybridization, but more 
probably to a gradual accumulation of mutant factors in balanced- 
lethal combinations. On the analog}^ of ^MuUer's Drosopliila case, 
aspecially, it might be expected that the latter would be the true 
explanation, particularly since self fertilization seems to be the rule 
in Matthiola. On this basis the term mutant type is used with some 
confidence in this paper, while the aberrant individuals have been 
called apparent mutants. 

We must not forget that some of the mutant types may arise, as 
with Oenothera gigas and 0. lata, by non-disjunction, or reduplication 
of chromosomes, and that this fact may determine tlieir heredity. 
This is not to be expected with the types whose factors show apparent 
coupling with singleness or doubleness, but it might be true of the 
apparently unlinked smooth-leaved type. A preliminary study of 
several types shows that the usual somatic number of chromosomes 
is probably fourteen, but that positive counts are difficult. While it 
might be very hard to demonstrate the regular presence of one extra 
chromosome in an individual or a type, it should be easy to decide 
between the diploid and triploid numbers. The large-leaved type is 
so strongly suggestive of 0. gigas that it would not be surprising to 
find the triploid number in the material now on hand for examination. 

In a preliminary paper on these types the writer (Frost, 1916) 
discussed some possible relations of mutation, heterozygosis, and 
partial sterility, with special reference to Oenothera, mentioning the 
po&sibility that special prevalence of heterozygosis in the genus may 
be, "in large part, a result rather than a eause of mutation." This 
suggestion is evidently justified even if much of the supposed mutation 
of Oenothera is really segregation, since it is highly probable that 



[156] 



MUTATION IN MATTHIOLA 299 

the peculiar plienomena depend on lethal factors or combinations of 
factors originally due to mutation. 

Another possibility there mentioned, advanced by Belling (1914) 
and since specially discussed by Goodspeed and Clausen (1917), is 
that of the occurrence of lethal combinations of certain factors which 
in other combinations may be in no way prejudicial to normal develop- 
ment. As the latter paper shows, it is probable that in certain 
crosses between "good species" most of the new combinations brought 
together in the formation of Fj gametes are incompatible witli the 
production of functional gametes. Perhaps in the case of Oenothera 
there ma.y exist within a species factors lethal in any combination 
when homozygous, and other factors lethal only in certain com- 
binations. 

A balanced-factor explanation for the inheritance of doubleness-' 
in Matthiola, a ease which ]\Iuller (1918) discusses, seems to have been 
first definitely stated by Goldsehmidt (1913), though he failed to pro- 
vide for one feature of the evidence, the deviation of the heredity 
ratio from 50 per cent. As has been shown (Frost, 1915), this 
peculiarity may be due to greater viability of the homozygotes (sterile 
doubles) during embryonic development, since the doubles are more 
viable in the mature seeds and more vigorous in later development 
(Saunders, 1915). In this case the "normal" factor is completely 
eliminated in favor of the mutant (sterile-double) factor in the 
formation of the sperms, and probably is partially eliminated in the 
formation of either the eggs or the embryos or both. 

Here the normal singleness (sporophyll) factor D may act as a 
lethal in the heterozygous parent, possibly from its general relations 
of growth vigor in the presence of the more vigorous d-carrying cells. 
If the lethal factor is situated in a distinct locus, evidently crossovers 
are at most extremely rare. It is true that Mi-ss Saunders (1911) 
finds that Fj hybrids with pure single forms produce functional 
single-carrying pollen ; with the pure single forms from which the 
original "double-throwing" mutants arose, however, this might not 
be true, or a lethal change may have occurred in the singleness factor 
itself rather than in a factor coupled with it. The Drosophila ease 
would suggest a lethal change in another locus of the single-carrying 
chromosome. 

In my paper of 1915 this lethal change in one chromosome ap- 
parently accompanying the mutation of D to d in the homologous 



-" For a brief outline of the genetic behavior of doubleness see the discussion 
of the experimental data for the smooth-leaved type. 

[157] 



300 MISCELLANEOUS STUDIES 

chromosome was considered puzzling. Evidently, however, it may 
have occurred in one chromosome before D mutated to d in the other, 
and even then may have produced its lethal effect. It is evident 
that if doubleness should arise in the absence of the lethal effect it 
would tend to be eliminated by the return of one-third of the singles 
to the homozj'gous condition in each generation. In fact, it is possible 
that the lethal change arose later than doubleness, as in the Droso- 
phila ease, or was brought in later by cross pollination, and happened 
to be preserved as a result of horticultural selection for a high pro- 
portion of double.s. 

A parallel-column comparison between the double type and the 
types especially discu.ssed above has already been given, in connec- 
tion with the smooth-leaved type. It will now be seen that this com- 
parison seems to apply to all mutant types, except early, that have 
been genetically tested, the principal differences between these types 
relating to the heredity percentage and the apparent presence or 
absence of linkage with the single-double factors. 

Prom the standpoint of its relation to genetic analysis the double- 
ness factor is remarkably similar to the sex factor in animals. There 
are two types in each generation, one heterozygous and the other 
evidently homozygous, and these types are produced by the fertiliza- 
tion of two kinds of eggs, produced in equal or nearly equal numbers, 
by a single kind of sperm. Although one of the somatic types is 
sterile, and the uniformity of the sperms produced by the other is due 
(evidently) to lethal action, the opportunity for chromosome analysis 
is similar to that with sex chromosomes. 

We may say that the doubleness factor and its normal allelomorph 
(d and D) are carried by chromosome pair I. Already we know 
several other pairs of factors evidently carried by this pair of chromo- 
somes. These are, to name only the mutant or possibly mutant 
member of each pair of factors: P (pale sap color) and W (colorless 
plastids), both studied by Miss Saunders (1911, 1911a) ; C (crenate- 
leaved), S (slender; possibly two factors), and ^V (narrow-leaved). 
As we have seen, the last three of these are probably lethal when 
homozygous, and one or more unidentified lethal factors may be con- 
cerned in the breeding results, while the doubleness factor affects the 
race much like a recessive lethal, since all dd individuals are completely 
sterile. 



1158) 



MUTATlOy IN MATTHIOLA SOI 



SUMMARY 

This paper describes the occurrence, characteristics, and heredity 
of certain aberrant plant types which decidedly resemble some of the 
"mutant" types produced bj' OeiiotJiera lamarckiana. The parent 
form is Matthiola annua Sweet, of the horticultural variety "Snow- 
flake." 

These aberrant forms may be called mutant types, since it is highly 
probable that they are originally produced by mutation. The aberrant 
individuals may be termed apparent mutants, since it may be con- 
sidered uncertain whether they iisually arise by immediate mutation 
or by segregation. The case acquires special significance because indi- 
viduals belonging to the mutant types, although the species is known 
to be typically Mendelian with respect to various characters, give 
erratic heredity ratios suggestive of Oenothera. 

At least eight types have been somewhat carefully studied, and six 
of these have shown their heritability in progeny te.sts. Several other 
types have been named, but for various reasons their distinctness is 
more or less doubtful. 

Some of the commoner types have each been produced by many 
parents, and in several pure lines isolated from the original com- 
mercial variety. The apparent mutants other than the early type com- 
pose about four or five per cent of the progeny of Snowflake and early 
parents, the separate types ranging down from about one per cent. 

Most of the mutant types are in general inferior to Snowflake in 
vigor, and the difference in development is greatly increased by certain 
unfavorable environmental conditions. The proportion of apparent 
mutants in cultures from Snowflake parents appears to be definitely 
lower where germination is comparatively poor. 

The mutant types differ from Snowflake and from each other in 
various respects. The early type is practically a smaller and earlier 
Snowflake. The other mutant types, on the other hand, differ markedly 
from Snowflake in vigor, fertility, and various form and size char- 
acters. Each type is named from some conspicuous characteristic 
difi'erence from Snowflake. but usually various other differences can 
readily be found. 

Somewhat extensive progeny tests have been made for five of the 
mutant types, and a little evidence secured for two or three other types. 



I 1.5fl I 



302 MISCELLAXEOUS STUDIES 

The early type is probably due to a single dominant mutant factor 
Segregating normally from the corresponding Snowfiake factor; the 
quantitative nature of its differences from 'Snowflake, however, makes 
positive determination of this point a matter of great difficulty. 

At least five other types plainly reproduce themselves, but about 
50 to 70 per cent of the progeny are usually Snowflake; no true- 
breeding individual of any generation of any of these types has yet 
been tested. Genetic work with most of those types has been much 
hampered or even prevented by low vigor and fecundity, and the 
aggregate data from progeny of parents of four types strongly indi- 
cate selective viability at germination. It has been determined by 
crossing that in three of the types the mutant factor (or factors) is 
carried both by eggs and by sperms. From these facts it seems prob- 
able that homozygotes of the mutant types are non-viable, and that 
severe selective elimination occurs during embryonic development ; 
or. in other words, that the mutant factor is imperfectly recessive for 
a lethal effect. 

In three types there appears to be linkage with the factor pair for 
singleness and doubleness of flowers, the mutant factor being coupled 
with singleness in the tested apparent mutants of two types, and with 
doubleness in the third type. With two other types these factors 
seem to be independent. No reversal of coupling has been found in 
later generations of the former two types, but on the scheme presented 
crossover singles should be scarce. 

For one type (crenate-leaved) a hypothesis based on the facts stated 
gives very closely the ratio obtained from selfed parents. Reciprocal 
crosses with Snowflake conform less clo.sely to the requirements of the 
hypothesis, but do not definitely contradict it. The slender type, 
which shows similar apparent linkage, seems to disagree definitely 
with the hypothesis; there is strong evidence, however, that slender 
individuals may differ genetically among themselves. 

A more complex scheme providing also for the usual origin of these 
types from Snowflake by segregation is briefly outlined. 

The selfing ratios are very suggestive of duplication of a chromo- 
some (non-disjunction), as in Oenothera lata, but it is hard to 
reconcile the cases of apparent linkage with this hypothesis. It seems 
probable that these three linked types have originated and are trans- 
mitted in the same general way as the double-flowered type, and that 
all of these four mutant factors (including double) represent changes 
of some sort within a chromosome of the same pair, which may be 



[1601 



ULTAIION IN UATIUIOLA :{(i:i 

iiuinbered I. ^liss Sanndcr's work shows that two flower-coh)!- factors 
also beh)ng to this linked group. 

The large-leaved type strikingly resembles Oenothera gigas, and it 
may prove to be triploid in nuclear constitution. In that case segrega- 
tion may be irregular and genotypieally intermediate individuals may 
be more or less frequently produced. 

It is jirdbable that further study of these types will help to explain 
the rcmarK'nlile ijciietic beliavinr of Oenallivra and of ('Urns. 



LITERATURE CITED* 

Atkinson, George P. 

]ni7. Quadruple liybrids in the F, generation from Oenothera miianx and 
Ooiothera pycnocarpa, with F~ generations and back- and inter- 
crosses. Genetics, vol. 2, pp. 21.3-260, 11 tables, 1 diagr., 1.5 figs. 

Babcock, Ernest B. 

191S. The role of factor mutations in evolution. Am. Naturalist, vol. 52, 
pp. n6-12S. 
Barti.ett, 11. 11. 

1917. Mutation in Mafthiola aiinmi. a " Mendelizing" species. [A review 
of paper of same title by IT. B. Frost.] Hot. Gaz., vol. 63, pp. 82-83. 
Bateson, Wlliam, and Saunders, Edith E. 

1902. Experimental studies in the physiology of heredity. I. Experiments 
with plants. Matthiola. III. Discussion. Roy. Soe. London, Re- 
liorts to the Evolution Committee, vol. 1, pp. 32-87, 12.'5-160, 1.5 
tables. 
Bateson William, Saunders, Edith R., and Punnett, Reginald C. 

190.5. Experimental studies in the physiology of heredity. Matthiola. Roy. 
Soc. London, Reports to the Evolution Committee, vol. 2, ]ip. 5-44, 
tables. 
1906. Ibid. Stocks. Ibicl.. vol. 3, pp. 38-53, 4 tables, 2 figs. 
Bateson, William, Saunders, Edith R., Punnett, Reginald C, and Killbt 
(Miss) H. B. 
1908. Experimental studies in the ph.ysiology of heredity. Stocks. Roy. 
Soc. London, Reports to the Evolution Committee, vol. 4, pp. 3.5-40, 
3 tables. 
Belling, John. 

1914. The mode of inheritance of semi-sterility in the offspring of certain 
hybrid plants. Zeitschr. f. indukt. Abstam.- u. Vererbungsl., vol. 12, 
pp. 303-342, tables, 17 figs. 
Bi.akeslee, Albert P., and Avery, B. T. .Tr. 

1919. Mutations in the jimson weed. Jour. Heredity, vol. 10, pp. 111-120, 
11 figs. 



* An asterisk prefixed to the date indicates that the pa]ier cited has not been 
seen by the present writer. 



304 MISCELLANEOVS Sl'VDIKS 

CoRBENS, Carl E. 

]900. uber Levkojenbastanle. Zur Kenntniss der Grenzen der Mendel 'schen 

Regehi. Bot. Centralbl., vol. 84, pp. 97-113. 
1902. Seheinbare Ausnahme von der Mendel 'schen Spaltungsregel fiir Bas- 
tarde. Deutseli. bot. Ges.. Ber., vol. 20. pp. 159-172, 4 tables. 

Davis, Bradley, M. 

1917. A criticism of the evidence for the mutation theory of de Vries from 

the behavior of species ot Oenothera in crosses and in selfed lines. 

Nat. Acad. Sci., Proe., vol. 3, pp. 705-710. 
Frost, Howard B. 

1911. Variation as related to the temperature environment. Am. Breeders' 

Assoc, Ann. Eept., vol. 6, pp. 3S4-395, 4 tables, 4 charts. 

1912. The origin of an early variety of Matthiola by mutation. Ibid., 

vol. 8, pp. 536-545, 5 tables. 

1915. The inheritance of doubleness in Matthiola and Petunia. I. The 

hypotheses. Am. Naturalist, vol. 49, pp. 623-636, 1 fig., 2 diagr. 

1916. Mutation in Matthiola annua, a " Mendelizing" species. Am. Jour. 

Bot., vol. 7, pp. 377-383, 3 figs. 

1917. A method of numbering plants in 2Jedigree cultures. Am. Naturalist, 

vol. 51, pp. 429-437. 

Gates, E. E0cgles. 

1915. The mutation factor in evolution. Jjondon, Macmillan, xiv + 353 pp., 

1 map, 114 figs., bibl. 

GOLDSCHMIDT, RlCH.\RD. 

1913. Der Vprorbnngsmodns der gefiillten TiCNkojenrassen als Fall geschleehts- 

begrenzter Vererbung? Zeitschr. f. indukt. Abstam.- u. Verer- 
bungsl., vol. 10, pp. 74-98, diagr. 

1916. Nochmals iiber die Merogonie der Opnotlierabastarde. Genetics, vol. 1, 

pp. 348-353, 1 pi. 

GooDSPEED, Thomas H., and Ci ausen, E. E. 

1917. Mendelian-factor differences versus reaction-system contrasts in hered- 

ity. Am. Naturalist, vol. 51, pp. 31-46, 92-101. 

Heribert-Nilsson, N. 

*19]5. Die Spaltungserscheinungen der Oenothera himarclHana. Lunds Uuiv. 
Arsskrift, vol. 12, pp. 4-131. (Review by Ben C. Uelmick in Bot. 
Gaz., vol. 63, 1917, pp. 81-82.) 

Muller, Hermann .T. 

1917. An Oenotlicra-like case in Drosopliila. Nat. ,\ead. Sci., Proc, vol. 3, 

]ip. 619-626. 

1918. Genetic variability, twin hybrids and constant hylirids, in a case of 

balanced lethal factors. Genetics, vol. 3, jip. 422-499, 1 table, 1 fig., 
1 diagr. 

Saunders, Edith E. 

1911. Further experiments on the inheritance of doubleness and other char- 
acters in stocks. Jour. Genetics, vol. 1, pp. 303-376, 8 tables. 
1911a. The breeding of double flowers. Fourth Intern. Conf. on Genetics, 

Proc, pp. 397-405, diagr. 
■ 1913. Double flowers. Roy. Hort. Soc, Jour., vol. 38, pt. 3, pp. 469^82. 



fui-ji 



MUTATION IN MATTHIOLA 305 

1913a. On the mode of inheritance of certain characters in double-throwing 

stocks. A reply. Zeitschr. f. indukt. Abstam.- u. Yererbungsl., vol. 

10, pp. 297-310. 
1915. A suggested explanation of the abnormally high records of doubles 

quoted by growers of stocks (Matthiola). Jour. Genetics, vol. 5, 

pp. 137-143, 3 tables. 
191 G. On selective partial sterility as an explanation of the behavior of the 

double-throwing stock and the petunia. Am. Naturalist, vol. 50, 

pp. -1S6-498. 

Siiui.L, George H. 

1914. Duplicate genes for capsule form in Bursa bursa-pastoris. Zeitschr. 
f. indukt. Abstam.- u. Vererbungsl., vol. 12, pp. 97-149, 5 tables, 
7 figs. 

' ' Student. ' ' 

1908. Tlie ]irobahle error of a mean. Biometrika, vol. 6, pp. 1-25, tables, 
4 diagr. 

1917. Tables for estimating the probability that the mean of a unique series 

of observations lies between — ro and any given distance of the 
mean of the population from which the sample is drawn. Ibid., 
vol. n, pp. 414-417, tables. 

Swingle, Walter T. 

1911. Variation in first-generation hybrids (imperfect dominance): its pos- 

sible exjilanation through zygotaxis. Fourth Intern. Conf. on 
Genetics, Proc, pp. 381-393, 10 figs. 

TSCHKKMAK, ErICH VON. 

*1904. Wcitcre Kreuzungsstudien an Erbsen, Levkojen u. Bohnen. Zeitschr. 
f. d. landw. Yersuchswesen in Oesterreich, 1904, pp. 533-638. 

1912. Bastardierungsversuehe an Erbsen, Levkojen, und Bohnen mit Riiclc- 

sicht auf die Faktorenlehre. Zeitschr. f. indukt. Abstam.- u. Yerer- 
bungsl., vol. 7, pp. 81-234, tables. 

Webber, Herbert J. 

1906. Pedigree records used in the plant-breeding work of the Department 
of Agriculture, in L. H. Bailey, Plant Breeding (New York, Mac- 
millan), pp. 308-319. 

DE Vries, Hugo. 

1906. Species and varieties: their origin by mutation. Ed. 2, Cliieago, Open 
Court Pub. Co., xviii + 847 pages. 

1918. Twin hybrids of Oenothera hoolceri T. and G. Genetics, vol. 3, pp. 397- 

421, 14 tables. 

1919. Oenothera riilirinervis, a half mutant. Bot. Gaz., vol. 67, pp. 1-26, 

tables. 
Yule, G. TJdnt. 

1911. An introduction to the theory of statistics. London, Charles Griffin & 
Co., xiii + 376 pages, 53 figs. 



ri6:!l 



306 MISCELLANEOUS STUDIES 



PLATE 22 

The Eaely Type 

Fig. 1. March 20, 1908. The single progeny of WG9. Plants from house M 
to the reader's left from stake, from house W to right of stake, from house C 
below. WG9-C10, the early apparent mutant, is the middle plant in the lower 
row. The stake indicates inches. 

Fig. 2. About May 1, 190S. WG9-C10 at the left, WG9-C9 (Snowflake) at 
the right. 



ri64i 



MVTATIOS L\ .U.irrUlULA 



307 













Fig. 1 




Fig. 2 



[ FROST 1 PLATE 22 



308 MISCELLANEOUS STUDIES 



PLATE 23 

The Eakly Type 

Fijr. 3. April S, liiOi). The single progeny of \VG9-C9 (Snowflake); arrange- 
ment as in figure 1. 

Fig. 4. April 9, 1909. The single progeny of WG9-C10 (heterozygous early). 
Warm-house plants partly at right of stake in lower row; arrangement other- 
wise as in figure 3. Compare with figure 3, house by house. 



[1661 



MVTATIOS IN M.ITTIIIIIL.I 



:',m 




Fisr. 3 




Fig. 4 



I FROST I PLATE 23 



310 MISCELLANEOUS STUDIES 



PLATE 24 

The Early Type 

Fig. 5. July 19, 1911. Lots 1 to 10, with lots 11 to 1-t mostly in sight at 
the right. Odd-numbered lot in nearer (west) half of each row. 

Fig. 6. July 19, 1911. Lots 19 to 28, with lots 15 to 18 mostly in sight at 
the left. 



[16S1 



ilCrATIOX IS MATTHIOLA 



311 




Fig. 5 




F\'J. 6 



1 FROST 1 PLATE 24 



312 MISCELLANEOUS STUDIES 



PLATE 25 

The Smooth-leaved Type 

Fig. 7. April 27, 1909. Smooth-leaved apparent mutants. Compare with 
figures 3 and 4 as to earliness, noting the difference in date. 

Fig. 8. May 29, 1914. Progeny of a smooth-leaved parent. Plant at right 
Snowflake single, the others smooth. 



1170] 



MriAiiox /.v M.irrii iDi.A 




Fisr. 7 




Fig. 8 



FROST 1 PLATE 25 



3U MISCELLANEOUS STUDIES 



PLATE 26 

The Smooth-leaved Type 

Fig. 9. June 28, 1913. Progeny of a smooth-leaved parent. Sniodtli single 
at left, Snowflake double at right. 

Fig. 10. Same date and parent as with figure 9. From left to right: Snow- 
flake double (also shown in figure 9), Snowflake single, smooth double. 



[IT'] 



Ml T Alios I.\ MATTlllOLA 



315 




Fig. 9 




Via. 10 



FROST I PLATE 26 



316 MISCELLAXEOrS STUDIES 



PLATE 27 

The Large-leaved Type 

Fig. 11. August 29, 1S14. Progeny of a large-leaved parent (28a), near 
the close of the hot Riverside summer. From left to right: large single, large 
double, Snowflake single (two, the first injured by aphids). 



11741 



UVTATION IX MATTHIOLA 



317 




r FROST 1 PLATE 27 



318 MISCELLANEOVS STUDIES 



PLATE 28 

The Large-leaved Type 

Fig. 12. July 8, 1916. Progeny of a large-leaved parent. Middle plant 
Suowflake; the rest large; all single. 

Fig. 13. July 8, 1916. Progeny of a large-leaved parent, more than a month 
older than those shown in figure 12. From left to right: large double,' Snow- 
flake double, large single. 



(1761 



MITATIOX IX MATTHIOLA 



319 




Fiff. \2 





!^B^^^^^Hi«> 




p^^^ 



Fig. 13 



I FROST I PLATE 2£ 



320 MISCELLANEOUS STUDIES 



PLATE 29 

The Crenate-i.eaved Type 

Fig. 14. April 6, 1909. Crenate-leaved apparent mutants. Note tlie varia- 
tion in leaf serration, and especially the slightness of the serration (or crenation) 
with the one cool-house plant (below). 

Fig. 1.5. April 14, 1911. Progeny of a crenate-leaved parent, grown in a 
cool greenhouse. The first two plants at the right are Snowflake, the rest 
crenate. 



[178] 



MUTATION L\ M ATTII lOL.I 



321 




Fitr. 14 




Fig. 15 

FROST 1 PLATE 29 



322 MISCELLANEOUS STUDIES 



PLATE 30 

The CRE.VATE-i.EAVEn Type 

Fig. 16. July 8, 1916. Progeny of a crenate-leaved parent. Prom left to 
right: crenate single (two), crenate double, Snowflake double. 

Pig. 17. July 8, 1916. Snowflake X erenate-leaved, P,. From left to right: 
smooth, Snowflake single, crenate double (two). 



[1801 



MUTAI'IUX IX MATTIIIOLA 



323 




Fie. 16 




Fig. 17 



FROST 1 PLATE 30 



324 MISCELLANEOUS STUDIES 



PLATE 31 

The Slender Type 

Fig. IS. April 27, 1909. Miscellaneous aberrant individuals, with two 
typical Snowflake plants (third from the left above, second from the left 
below). In ujiper row: second from left, narrow double; second from right, 
slender double. In lower row at left, slender single (2.5b). 

Fig. 19. April 14, 1911. Progeny of a slender jiarent (2.5b). Two at the 
right Snowflake, the rest slender. 



11821 



MirATlUS IX MATTIIIULA 



325 



&►.-<*• *-»Mi.*JBi. 








'dC-^S 'dtnX^oW^^ ^* 


5/A 




Jl 





Fi". 18 



IS 








1 


-:cA9, 




_B " 1 ,^ ll- 


^Mk::=» t,.._^li_-. — il r. 







Fi". Ill 



FROST 1 PLATE 31 



326 MISCELLANEOUS STVDIES 



PLATE 32 

The Slender Type 

Fig. 20. June 3, 1914. Progeny of slender jiarents. From left to right: 
slender single, slender double, Snowflake double. 

Fig. 21. July 7, 1916. Snowflake X slender, F,. Middle plant Snowflake; 
tlie otliers slender; all single. 



11841 



ilVTATlOX IX MATTIIIOLA 



327 




Ficr. 20 




Fig. 21 



I FROST 1 PLATE 32 



328 MISCELLANEOUS STUDIES 



PLATE 33 

The Narrow-leaved Type 

Fig. 22. April 13, 1011. Narrow-leaved apparent mutants. 

Fig. 23. June 3, 1914. A narrow-leaved apparent mutant among progeny 
of a erenate-Ieaved parent. From left to right: narrow double, crenate single 
(two). 



[186] 



Mrr.iriox ix matthiola 



312!) 





[ FROST ] PLATE 33 



330 MISCELLANEOVS STUDIES 



PLATE 3-4 

The Narrow-leaved and Small-smooth-leaved Types 

Fig. 24. June 28, 1915. A narrow-leaved apparent mutant among F, progeny 
from Snowflake X slender. Narrow double at left; the rest SnovviJake single. 

Fig. 25. April 14, 1911. Miscellaneous aberrant plants, some being apparent 
mutants. From the left: first and fifth small-sniootli, tliird stout dwarf, seventh 
slender. See text. 



11881 



Ml T.iriOX l.\ M.ITTIIIOLA 



331 




Fig. 24 




Fig. 25 



FROST I PLATE 34 



332 MISCELLANEOUS STUDIES 



PLATE 35 

The Nakrow-d.vek-leaved T\pe 

Fig. 2G. June 3, 1914. A narrow-dark-leaved apparent mutant among 
progeny of a narrow-leaved parent. Third plant from left narrow-dark single; 
the other three Snowflake double. 

Fig. 27. June 28, 1915. Progeny of a "small-convex-leaved(f ) " parent 
(27a). From left to right: narrow-dark single, Snowflake double, smooth single. 



(1901 



ilLTATlO.X I.\ MAlTillOLA 



333 




Kiir. -M 







V\s. 



FROST I PLATE 35 



OCEAN TEMPERATURES 



BY 

GEORGE F. McEWEN 



OCEAN TEMPERATURES, THEIR RELATION 

TO SOLAR RADIATION AND 

OCEANIC CIRCULATION 

QUANTITATIVE COMPARISONS 
OF CERTAIN EMPIRICAL RE- 
SULTS WITH THOSE DEDUCED 
BY PRINCIPLES AND METHODS 
OF MATHEMATICAL PHYSICS 



GEORGE F. McEWEN 

Oceanographer of the Scripps Institution for Biological Research 
of the Uni^'ersity of California 



CONTENTS 



Introduction. The place of mathematical methods in researches on oceano- 
graphic problems 337 

Solar radiation and surface temperature, assuming the average rate of flow of 
the water to be zero 338 

Preliminary discussion, and statement of certain generally accepted 
conclusions as to the process by which the water gains and loses heat 338 

Statement of assumptions, mathematical formulation of the problem and 
its solution 339 

Determination of the numerical values of the constants in the solution.... 344 

Observed and theoretical lag of temperature maxima and minima behind 
the radiation ma.xima and minima; comparison of computed and 
observed normal temperatures 348 

Numerical estimates of the coefficient of absorption of solar radiation 
in sea water 350 

Deduction of the change in surface temperature produced by a horizontal flow 
of water 352 

Preliminary discussion, statement of assumptions, and mathematical 
formulation of the problem 352 

Solution for the case in which the flow is constant 356 

Solution for the case in which the flow is a periodic function of the time ,,. 359 

Solution for the particular case in which the time interval is so small 
that the solar radiation may be assumed to depend only upon the 
latitude 360 

The rate of horizontal flow in the North Pacific off the California coast from 
latitude 40° N to 30° N and in the North Atlantic off the west coast of Africa 
from latitude 30° N to 20° N 362 

The rate of flow off the coast of California deduced from surface tem- 
peratures 362 

The rate of flow deduced from temperature data compared with that ex- 
pected from the empirically ascertained relation of winds to currents 
and with direct observations on currents 363 

The surface current prevailing for a short time interval near the north- 
west coast of Africa, estimated from surface temperatures, com- 
pared with direct observations and with results deduced from the 
empirically ascertained relation of winds to currents... 364 



336 MISCELLANEOUS STUDIES 

The relation of the temperature to time, depth and rate of vertical flow in the 
depth interval from 40 to 600 meters 367 

Statement of assumptions and mathematical formulation of the problem 367 

Solution for the case in which the vertical flow is constant 369 

Solution for the case in which the vertical flow is a periodic function of 
the time 372 

Numerical values of the constants in the solution, determined from tem- 
perature observations in the Pacific near San Diego 374 

Comparison of theoretical and observed monthly temperatures at depths 
from 40 to 600 meters in the San Diego region 382 

Solution of the problem of temperature reduction due to upwelling, with 
numerical appHcations relative to the 40 meter level in the San Diego 
region 382 

Deduction of the change in surface temperatures due to a vertical flow of water 
near the surface 388 

Statement of assumptions and mathematical formulation of the problem 
and solution for the case in which the flow is constant 388 

Solution for the case in which the flow is a periodic function of the time. . 391 

Theoretical reduction of the surface temperature for each month in the San 
Diego region due to upwelling, and comparison with observations 393 

Deductions relative to oceanic circulation in the San Diego region, based on 
Ekman's hydrodynamical theory 397 

Deduction of the upwelling velocity in the San Diego region from the observed 
relation of salinity to depth, and comparLson with that deduced from tem- 
perature data 406 

Conclusion 415 

Literature cited 419-421 



OCEAN TEMPEltATVnES 337 



INTRODUCTION 

The Place op IMathematical Methods in Researches on 
oceanographic problems 

The present paper deals with the formulation and solution of 
several quantitative problems suggested by data on ocean winds, 
temperatures, and circulation. Before formulating these problems 
a brief general discussion of the place of mathematical methods in 
oceanographie researches is given. 

The process of testing physical laws in the laboratory is greatly 
facilitated by devising appropriate experiments in which the variables 
are largely under the control of the investigator. Even under these 
favorable conditions the actual phenomena are too complex for de- 
tailed representation in a mathematical formula, and an appropriate 
simplification by abstraction is required to formulate problem.s that 
are amenable to mathematical treatment. This is true in a much 
greater degree of the more complex phenomena occurring in nature ; 
yet a rigorous mathematical treatment of natural problems capable of 
yielding results in agreement with oliservations, while in general more 
difficult, is necessary and fully justifies the increasing attention being 
given to terrestrial and cosmic physics. 

The actual phenomena of heating and cooling of the water in the 
ocean are far too complex to be considered in detail. Therefore, in 
order to apply rigorous mathematical reasoning to these phenomena, it 
is necessary to devise a comparatively simple ideal system which would 
behave in essentially the same way as the actual one with reference to 
the observations in question. Certain problems can then be formulated 
definitely in such a way as to permit of the precise calculation of 
results, the comparison of which with observations tests the practical 
value of the abstract system. 

It is fortunate for the problems considered in this paper that the 
proper choice of the simple assumptions needed in devising the ideal 
system is facilitated hy certain general results of numeroi;s and extended 
ocean as well as laboratorij observations. An abstract system foinided 
on such assumptions would in general agree much better with the 
conditions in nature than one in which the assumptions were hypo- 
thetical or carried over from some other field. Evidently deductions 
from any group of simple assumptions cannot have the same degree 



338 MISCELLANEOUS STUDIES 

of certainty as direct observations, since the ideal system cannot con- 
form accurately to all the details of the phenomena of the actual one. 
However, if in this way a logical and reasonably accurate description 
of a wide range of physical quantities is ol)taincd there is good reason 
to believe that deductions or predictions relative to ciuantities not yet 
observed will be in agreement with the facts. This is especially true 
if two or more lines of reasoning converge to the same conclusion. 

WJien it is impossible or impracticable to make tlic appropriate 
direct observations the theoretical resuUs must be regarded as the 
best estimates, even though it is not impossible that future observations 
may shoxv important deviations from theory. Finally, while the exist- 
ing observations may be logically described by means of the ideal 
system, and deductions based on it, extended results reached by apply- 
ing purely deductive methods to the ideal system are not substitutes 
for a correspondingly extended series of new observations. The neces- 
sity for making observations will always exist. 

Solar Radi.\tion and Surface Temperature, Assuming the 

Average Rate of Flow^ op the Water to be Zero 

Preliminary discussion, and .statement of certain generally accepted 

conclusions as to the way in which the water gains and loses heat. 

In order to have a basis for estimating the effect of circulation on 
ocean temperatures it is necessary to work oiit quantitatively the rate 
at wliicli tlic heat of tlie water is gained and lost luulcr the more 
sim{)le condition of no flow. This will be done by devising an ideal 
ocean, based on assumptions agreeing as nearly as possilile with the 
following conclusions which are founded on numerous and widely 
extended ocean observations. 

1. The primary source of heat is the radiant energy of the sun, 
both direct and diffuse, that penetrates the water (Murray. 1912, p. 
225, Gehrke, 1910, p. fi7. nclland-IIaiiscn. 1911-12, pp. (i-1-66). 

2. Absorption of this radiation directly heats the water in the 
upper layers (Nanseu, 1913, pp. 21-22), and only a small fraction of 
this radiant energy penetrates below 25 meters (Kriimmel, 1907, pp. 
253-270, Helland-Hansen, 1911-12. pp. 65-fi8, and Knott, 1903-05). 

3. There is always a complex vertical circulation (Helland-IIansen, 
1911-12, p. 68. Gehrke, 1910, p. 68, Nansen, 1913, p. 21, ilurray. 
1912, p. 226) due to a lack of balance of the many forces acting on 
the water particles. The resultant vertical flow through a finite sec- 
tion due to this motion may be very small and may be either u|)ward 



OCEAN TliMl'EKATVliKS 339 

or downward. That is, at the same time, some portions of the water 
are moving upward and other.s downward, thus tending to mix up the 
water at diiferent levels. In this problem the resultant of the upward 
and downward flow will be assumed to be zero. 

4. This "mixing process" is most intense in the layers nearest 
the surface, owing to wave motion and other surface disturbances due 
to wind, but is present in some degree at all depths (Gehrke, 1909, 
p. 12, Murray, 1898, p. 127). 

5. The amount of heat transferred from one level to another by 
conduction through the water is a negligible fraction of that carried 
by the water particles themselves as a result of the mixing process 
(Gehrke. 1909, p. 12). 

6. The mean animal rate of change of temperature with respect 
to latitude is practically independent of the depth within the upper 
hundred meters. This is revealed by a study of the average tempera- 
tures of the North Pacitie, tabulated with respect to latitude, longitude, 
and depth (Schott, 1910. p. 14). 

7. At the time of year when the surface temperature is a minimum 
there is practically no variation of the temperature with respei^t to 
depth in the upper thirty meters (McEwen, 1916, p. 272). 

Statement of assumplions: mathematical formulation of llu problem 

and its solution. 
Let K^f^(L,t) equal Q,. the amount of radiant energy available 
per montli per unit area of horizontal surface at the latitude L and 
time t, where K^ is proportional to the solar constant and /, {L,t) 
is a function of the latitude L and the time t. Let Q equal the amount 
of radiant energy used directly in heating the water, that is, the 
amount passing into the water. Also let 

y equal the distance in meters from the surface of the water, the 

positive direction being downwards, 
or equal the specific heat of sea water per unit volume, 
6 equal the temperature, centigrade. 

t equal the time, the unit being 1 month, and t equal 1 for January, 
^1 equal a temperature assumed to depend only on the latitude and 

depth y, and 
pi equal the average transmission coefficient of sea water for the 
solar radiation, that is, tlie proportion of radiation at any level 
that passes through unit thickness of water measured from that 
level. 



340 



MISCELLANEOUS STUDIES 



Since the solar radiation consists of a series of waves of varjing 
length, each having a different coeffieient of transmission (Murray, 
1912, p. 248, Kriimmel, 1907, p. 263), the use of a single average value 
is only a simple approximation to the true relation. 

No analysis will be attempted of the complex way in which the 
heat in an element of volume, specified by given values of y and L, 
is lost. This loss depends upon evaporation at the surface and on 
the mixing process at all depths, and the rate of evaporation increases 
as the temperature increases. Also heat tends to flow from regions 




Fig 



of high temperature to those of low temperature (Gehrke, 1910. p. 68). 
It seems reasonable to suppose, therefore, that the rate of loss would be 
greater, the greater the temperature. 

Although the precise manner in which the rate of loss of heat 
depends upon the temperature is not known, some definite form of 
relation must be assumed in order to formulate the temperature 
problem mathematically. For simplicity assume the rate of loss at 
any depth to be proportional to {6 — ^j ) at that depth, where 6^ is a 
function of the depth and latitude only. Consider now the time rate 
at which heat is gained and lost in a given rectangular element of 
volume of unit cross section and thickness dy whose upper sxirface is 
at the depth y (fig. 1). 

The rate of change of heat in this volume element is evidently 



d[(T(dy)e] 
dt 



-o{,dy)~ 



(1) 



since the volume specific heat multiplied by the volume of the element 
equals the change in the amount of heat per degree change of tem- 
peratui-e. 



OCEAN TEMPEEATVEES 341 

The rate of gain of heat in this element of volume due to the 
absorption of solar radiation equals the difference between the rate 
at which the radiant energy passes in through its upper surface and 
out through its lower surface. At the upper surface the rate is 
^/8i» and at the lower surface it is Q^^"*''". Therefore the rate of 
gain diie to absorbed radiation is 

(?;3/ — (?^/*''« = (?/?/ (l — A"^) = — <?(loge/?,)/?A?:V (2) 
since 

1 — /J/^^i— [1 +(iog/3t)'?.'/] ==— (iog/8.)f?y. 

The rate of loss of heat will be assumed to be k(x{9 — ^Jr/y where 
k is a function of y only. 

Equating the rate of change of heat in the element to the rate of 
gain from solar radiation less the rate of loss, we have the following 
differential equation 

(3) 



(41 
after division by achj. 

Let L^Li-\- X where L^ is a standard latitude chosen arbitrarily 
and X is the distance in degrees from this position, x is positive for 
latitudes higher than L, and negative for lower latitudes. The function 
fj{L,t), (p. 339). then becomes f{x,t), which expresses the way in 
which the radiation varies with respect to latitude and time. The 
precise form ot f{x,t) is unknown; however, estimates of the amount 
of radiant energy available at the earth's surface made by Angot 
(Hann, 1915, p. 40) can be closely approximated to within a ten-degree 
interval of latitude by an expression of the form 

Qi ^= /I'l [ (di -\- a^x) cos at -{■ a^x + 1] (5) 

TT . . . 

where a = — , and the coefficient of cos at is negative. 

n 

Assuming the amount of energy Q that enters the water to be pro- 
portional to the amount available ^i 

Q = K[ {a^ + a^_x) cos at + a.,x + 1] (6) 



.(cZy)^=. 


—Q(\ogli,)py(hj — -ka{e- 


-6,)dy 


diich becomes 

M 
dt 


CT 


-6,) 



342 MISCELLANEOUS STUDIES 

where the constant K s K^, since the amount of energy used cannot 
exceed the amount available. Equation (4) then becomes 

66 Eilogp,)^,". 



[(a, + a,z) cos at -\- a.,x + 1] —k{e — e^) (7) 
K log 13, Kb, 



dt 
Let 

K Incr R K h 

B (8) 



where B is a constant and 



p, = e-^- (9) 



where h, is the absorption coefficient (Kriimmel, 1907, p. 263). 
Equation (7) then reduces to the oi'dinary linear differential equation 

flft 

— j^l-e=B[ia,+ a,x) cos at + a,x + 1] e-'« + M, (10) 

Therefore 

e=e-"|e-''"/c'■■'B(a,+ff,,r)cosa/rff+f-''^"jV*■'(a,.r+l+/,^(9Jd«+F(.r,.v)| 

(11) 
where F(.r,y) i.s an arbitrary function of x and .//. Integrating 
equation (11) gives 

6=Be-^^y{a,-^a„x) ~-, 1 p-^-^ \r6,+e-^<F{x,y) 

a"-|-/i'" K 

(12) 
which can be readily transformed into 

^ 5(a, +a„.r)e-"'" , , , , .„ ( Ba,x , B] , „ ^qi 

fl= VI '- eos (a# — £)+<'-''-» -^ —r^+ — ^ + ^1 (13) 

whore 

tan£ = - (14) 

and only the periodic part of the integral is retained. 

If 6, is assumed to be independent of .r the latitude gradient (j 
of the mean annual temperature is, from equation (13"). 

g = e-i>^v{^\ (15) 



Therefore, since g is independent of \j (sixth statement, p. 339) 

k^l;€-"^v (16) 

where k, i.s a constant. That is, 



OCEAN TEAirKBATPEES 343 

Corresponding to the time of year <„ when the surface temperature 
has the minimum vahie 6g equation (13) becomes 

Since the eoelficient of cos (at — t) is negative (see p. 341) cos {at^ — e) 
must equal plus 1; therefore from the seventh general statement 
(p. 339) 

B(a,±a^^^ (19) 

where 6, is a constant. 

Making use of the results just found equation (13) becomes 

e = m±M^[cO. iat-.)-l] +^ + f + ^3 (20) 



where 



^--=i=v^^ ^''^ 



The small variation in temperature with respect to depth in the upper 
six meters indicates that these upper water layers are very thoroi;ghly 
mixed (]Miehael and ]McEwen, 1915. 191(i). Accordingly temperatures 
in this 6 meter interval will be computed by using 3 meters, the 
average value of the depth. That is, (y — 3) will be substituted for 
1/ when the depth exceeds 6 meters and the constant value (6 — 3)= 3 
for all depths between and 6 meters. From equation (20) it follows 
that at the time of minimum temperature the temperature is inde- 
pendent of the depth y in accordance with the seventh general state- 
ment (p. 339). But the latitude gradient which is the part of the 
coefficient of x in equation (20) not involving the time is 

Ba„c-'''y , Ba, 



This is not in accordance with the observed fact that the latitude 
gradient is independent of ;/.■ but the relative error will depend ni)on 
the ratio of the first term to the second term, and may not be important. 
As will be seen later (p. 345) it proves to be a negligible error if we 
add to 6^ of equation (19) the term Ba^xe-^ 

Therefore equation (20) with this modification and the use of (y — 3) 
for the depth ij gives the approximate form of the relation between 



344 MISCELLANEOUS STUDIES 

temperature, time, depth, and latitude, in accordance with the assump- 
tions and general results of temperature observations already stated. 
The modified equation is 

"— ^ 1^ - ' .[cos (o^— e)— l]+^7-^.T M ' = ' " 



(22) 
Also from equations (19) and (20) 

B Ea r B(a -4- a T')e-6i(!/-3) 

(g— gJ^^ + £^ + -^li^l± gg^l^ COs(a/-c) (23) 

'>'i ''1 ^/a--\-k- 

where 

a a 



tan e = 



A- k^e-o^'v-^' 



Determination of the numerical values of the constants in the solution. 

In applying mathematical methods to physical problems the 
functional relation between the variables involves certain constants 
which must be determined from observed values of these variables. 
The constants in equation (22) are 

flj flo a^ a A-j O.f B and 6,. 

Also from equation (8) we have 2? = — —. The first four constants 
are found by fitting the function 

J^i [ (^1 + O"!^) cos at -\- a^x -\- 1] 

(equation 5) to the estimated values of solar radiation, as given for 
example by Angot's tables (Hann, 1915, p. 40). The next three 
require observations on temperature. For example, they can be found 
from the observed values of the normal annual range of temperature 
at a .series of latitudes and from the mean annual temperature at 
these latitudes. 

The coefficient of absorption h^ can be estimated from direct meas- 
urements of the intensity of radiation in the ocean at different depths 
(Grein, 191.3), or from observations on water samples taken to the 
laboratory (Petersen, 1912, p. 39). Also an indirect estimate can be 
made from temperature and .solar radiation data (pp. 350-352) by 
means of equation (22). However, in the problem of .surface tem- 
perature in which the vertical flow is neglected the value of b^ is not 
required. 



OCEAN TEMPEEATVSES 



345 



Choosing 30° N for tlie standard latitude L^. tlie data on solar 
radiation taken from Angot's tables and based on the atmospheric 
transmission coefficient of 0.60 gives the following values of the first 
foiir constants : 



a., : 



-.0128 a3 = — .0159, a=-= 

6 



0.523. 



ttj = — .47 

A later and more accurate estimate of the radiant energy' available at 
the ocean's surface (Schmidt, 1915, p. 121) gives smaller values, on 
the average, than those of Angot; also instead of the value — .0159 

53 



for ^3 his re.sults give — "C -in, ^ — .0244, which will be iised in 
in this paper. 

Kriimmel (1907. p. 413) gives the observed normal mean annual 
temperature and the normal annual temperature range for the surface 
of the ocean corresponding to a series of latitudes. These values are 
in part presented in the following table. 

Table 1 

Observed values of the normal mean annual temperature and the normal annual 
range for the surface of the ocean at latitudes 10° N to SO N 



North latitude 


10° 


20° 


30° 


40° 


50° 






Mean Annual temperature . 

Annual range 

Half Annual range 


27.2 
2.2 
11 


2.5.4 
3 6 

1.8 


21.3 
6.7 
3. 35 


14.1 

10.2 

5.1 


7 9 

8.4 
4.2 


X 


-20° 


-10° 


00° 


+ 10° 


+20° 





From the tabulated values it follows that the gradient of the half 
range is .175 and the gradient of the mean annual temperature is .72 
from latitudes 30° N to 40° N. Let m^ equal c'"'^ where 3 is the mean 
depth of the upper homogeneous layer. From these values and 
equation (22) we have 



Ba^yriy 






Va" + A-fmi" 



= —.175 



3 35_Ba^r _^/_fc^y-| 



and 



Ba, 



= —.72 



(24) 



(25) 



(26) 



346 MISCELLANEOUS STUDIES 

in which the last members of equations (24) and (25) are approxi- 



mately correr-t if l~ — -) is small. 



Substituting the numerical values of a^ a. a, and a from page 345 
we have 

From equations (2-4) and (27) neglecting -(— ^ — -) we have the first 

approximation 

29.5 AvHi X 1-910 X (—-47) =—3.35 (28) 

from which 



Therefore 



and 



^''■»'-^ 29.5XL910X.47 =-^^^^- 



1 _^ 1/2 (A!!liy = 1.0292 
k^m^ = 1.0292 X .1265 = .1302 (29) 



^ ^ 29.5 X. 1302 ^3j4 ^3^^^ 



Similarly from equations (25) and (27) we have 
29.5 k,tn, X 1-910 X -0128 = .175 



from which 



Therefore 



7. „, -^^ 9407 

'^~ 29.5 X 1-190 X .0128 



and 



1 + 1/2 (^hUlij '=1.1075 
k,m, = 1.1075 X .2427 = .2688 (31) 



g ^ 29.5 X .2688 ^ 7.927 .^^^ 



The difference between the values of B and k^ found by th&se two 
methods of computation is due to the fact that the ratio between the 



OCEAN TEMPERATVRES 347 

half i-ange of radiation at the standard latitude to the gradient of 
the half range of the radiation is not quite consistent with the ratio 
of the half range of temperature at that latitude to its gradient. 

It seemed best to take the average of the two values and to apply 
corrections to a^ and a„, making them agree with the temperature 
data; then the difference between the corrected values a\ and a\ and 
the original values will indicate the magnitude of this discrepancy 
between temperature data and solar radiation data. Accordingly 

12(M^+I:^)=.^ = B = ^ (33) 

and 

1/2 (.1302 + .2688) = .1995 = k^m, = .20. (34) 

From equations (2-1) and (25) the new values a\ and a'„ of a^ 
and a„ are 



3.35V.274+.04^-3.35V.314__31S ^^.^ 



' Bm^ 5.9 

and 



-.175V.314__Q^gg_ (36) 



5.9 

Substituting these niunerical valuations in equation (22) and deter- 
mining ^3 from the observed surface temperature 21?3 when x equals 
we have, expressing the angle in degrees 

— (—.318 — .0166a-) c-^^^y-^'> 

e= I" [cos (30f — €)— 1] 

y.274 + .04(9!) 

_. 72. -i£i£mi+ 17.95 (37) 

V.274 + .04 



where 



tan e = 2.62 ,^\^ . (38) 



For the surface temperature, put y ^= 6 and we have 
_5.9(-.318-.0166x) [,,, ^,ot -e9y-l]-.12.- '-'^-''''^^ 



.56 L-" V""- -/ -J •■— 5g 

(39 
-f 17.95 = — (3.35 + . 175x) cos (30< — 69) ° + 21.30 — .72x. 



348 MISCELLANEOUS STUDIES 

In the same way the following values of the constants for the 
latitude interval from 20° N to 30° N were determined: 

«', = — .343, a'„ = — .0159, ag^— .0161, ;,-im,= .217, 

— i = the latitude gradient = — .41, 

— .155 = the latitude gradient of the half range, 
„ 5.535 , . .523 m, m^ 

Hli 217 6-*''"-=" g-lh'U'^i 

Substituting these numerical values in equation (22) gives for the 
siirface temperature 

^ = — (3.35 + .155x) cos (30< — 67.5)° + 21.30 — .41.r (40) 

Observed and theoretical lag of temperature maxima and minima 

behind the radiation maxima and minima. Comparison 

of computed and observed normal temperatures. 

The value of «=69°, corresponding to the latitude interval 30° N 
to 40° N, was deduced from theory; and since 30° corresponds to 

69 
one month, 69° corresponds to —^2.3 months, the theoretical lag 

oU 

J. ,, ( maximum ) , , , i • t ,i ( maximum ] j- j.- 

or the ^ • • f temperature behuid the ^ • ■ radiation. 

( minimum ) '■ ( minimum \ 

The theoretical time of the maximum temperature is therefore 
8.3, or about halfway between August and September ; while the 
theoretical time of the minimum temperature is 2.3, or about halfway 
between February and March. According to Kriimmel (1907, p. 407) 
from numerous and extended oceanic observations the average time 
of the lowest temperature is February (t = 2) and that of the highest 
is August it = 8). 

Again, from the three curves (Makaroff, 1894, pi. 26) giving the 
mean monthly surface temperature observed in the North Pacific 
between latitudes 30° N and 45° N the minimum temperature occurred 
when 

t = 1.8, 3.0 and 2.5 

and the maximum temperature occurred when 

t = 8.1, 8.3 and 7.8 

respectively. The average of the above values of t is 2.4 for the 
minimum and 8.1 for the maximum. Thus the predicted value of the 



OCEAN TEMPEBATISES 



349 



lag agrees very closely with the obseryed value. Since this value was 
computed from that of tlie period of the temperature change, which 
is accurately l<nown to be twelve months, and from the foregoing 
determination of the value of k^nii this agreement between theory and 
observation affords strong evidence in favor of the reliability of the 
vahie .2 adopted for }t\i)ij. which is an important constant in the 
investigation of ocean currents presented later. 

From numerous surface temperature observations in the Pacific at 
long. 173° W, lat. 20° N (Puis, 1895, pis. 1-4), off Madeira in the 
Atlantic, lat. 32° 30' N (Kriimmel, 1907, p. 407) and off Yokohama 
and at long. 140° W in the Pacific, lat. 35° N (Kriimmel, 1907, p. 408; 
Thorade, 1909. pis. 1-3) it was found that the mean annual tempera- 
tures agreed well with the normal values for the latitude. Therefore 
there is good reason to suppose that the condition giving rise to the 
temperatures at these places approximates closely to the normal con- 
dition. Thus a comparison between the theoretical monthly tempera- 
tures given by equations (39) and (40) with the observed vahies will 
give a still more detailed test of the theory (table 2). 

Table 2 
Theoretical and ohserved normal surface temperatures at a series of latitudes 



Latitude 20° N 


21° 18' N 


30°N 

t 

o 

18 °7 
18.0 
18.2 

19 2 
20.8 
22.6 
23.9 
24.6 
24.4 
23 3 
21.6 
20.3 


32° 30' N 


35° N 


40°N 


j3 

"c 

O 
1 

2 
3 

4 

5 

6 

7 

8 

9 

10 

11 

12 


s 

H 
24 °0 
23.6 
24.0 
24.7 
25.6 
26.5 
26.8 
27.2 
26.8 
26.1 
25.2 
24.3 


-a 
(1) 

> 

tD 

73 
J2 
O 

24 °1 
24.2 
24.7 
24.7 
24.9 
25.9 
26.3 
26.7 
26.7 
26.4 
2.5.8 
24.8 


i 

Q 

+ °1 
+ .6 
+ .7 
+ .0 
— .7 
-.6 
-.5 
-.5 
-.1 
+ .3 
+ .6 
+ .5 


g 

23 °3 
22.9 
23.3 
24.1 
25.2 
26.1 
26.5 
26.9 
26.5 
25.7 
24.6 
23.7 


1 
1 
? 

21 °6 

20.8 
21.6 
22.1 
23.0 
24.4 
25.3 
25.8 
2.5.1 
24.4 
23 
21.1 


c 

a 

-1°7 
-2.1 
-1.7 
-2.0 
-2.2 
-1.7 
-1.2 
-11 
-1.4 
-13 
-1.6 
-2.6 


t 

g 

H 
16 °6 
15.7 
16 
17.1 
18.9 
20.9 
22.4 
23.2 
23.1 
21 9 
20.1 
18,1 


1 
1 

O 
18 °0 
17.2 
17.1 
17.9 
18.7 
20.3 
21.8 
22.9 
23.2 
22.1 
20.6 
19.0 


S 
c 

5 

+ 1^4 
+ 1.5 
+ 1.1 
+0.8 
-0.2 
-0 6 
-0.6 
-0.3 
+0.1 
+0.2 
+0.5 
+0.9 


1 

14 °4 
13.6 
13.8 
15.1 
17.0 

19 2 
21.0 
21.9 
21.6 

20 3 
18.4 
16.2 


-a 

1 

13 °4 
13.8 
13.4 
14.2 
17.2 
18.5 
21.6 
23.5 
22.7 
20.0 
17.2 
16.4 


V 

a 

5 

-1°0 
+ .2 

- .4 

- .9 
+ .2 

- .7 
+ .6 
+ 1.6 
+ 1.1 

- .3 
-1.2 
+ .2 


H 
lOfl 
9.1 
9.3 
10.9 
13.3 
15.9 
18.1 
19.1 
18.9 
17.3 
14.9 
12.3 


Mean 

annual 

values 


25.4 


25.5 


+ .1 


24.9 


23.2 


-1.7 


21.3 


19.5 


19.9 


+0.4 


17.7 


17.5 


_ 2 


14.1 



*Air temperatures at Honolulu (Monthly Weather Review, 1903, pp. 225-226). 



350 



MISCELLANEOUS STUDIES 



It appears that the theoretical resultfs agree well with observation. 
If the difference between the theoretical and observed mean annual 
temperatures due to the average departure of the local conditions 
from the normal is applied as a correction to the observed monthly 
temperatures the agreement between theory and observation is very 
close. 



Numerical estimates of the coefficient of absorption of solar radiation 

in sea water. 
A lower limit of the value of the absorption coefficient h^ can be 
determined from quantities depending on surface temperatures and 
the amount of solar radiation at the siirface of the ocean by the fol- 
lowing method. The value of A'l (p. 344) obtained from Angot's data 
(Hann, 1915, p. 40) was v 

B:i=5.18X10'\ 

where A is the solar constant. The more accurate result of Schmidt's 
later investigation (1915, p. 121) (p. 345) is 

A\= 217 X 30 X 10* = 3.255 X lO'A. 



Since B 



Kb, 



K . 



and i?//^^5.9 (p. 347) 

94 X 10" X 5.9 5.54 



K. 



mj). 



m^b. 



XIO". 



But since -r;r- is the ratio of the amoiuit of energv supplied to the water 

by solaj- radiation to the amount available at the surface, -v;^ < 1. 

A, 



Therefore 



5.54 X 10" 



5.54 



A\ m,b, X 3.255 X lO'A 32.55 m,b,\ 
Using the accepted value 2.00 for A we have 
m,b, = b,e-^''^ > .0851. 
Table 3 



<1. 



b, 





.05 


.10 


.12 


.15 


.20 


.25 


.30 


be~''" 





.043 


.074 


.083 


.096 


.110 


.118 


.122 



OCEAN TEMPEliATVUES 351 

From the values of 6,c"^''> given iu table 3 it follows that b^ > .12 
or e-''i = /?j < .887 where /Jj equals the proportion of incident light 
that passes through one meter of sea water. Direct observations of 
the proportion of solar radiation passing through samples of sea water 
taken from the Nordlichen Ostsee and the Bottensee (Petersen, 1912, 
p. 39) give values of /?j varying from .60 to .86, which are less than the 
upper limit .887 deduced from theory. 

The variation with respect to depth of the heat absorbed by the 
water tends to maintain a temperature gradient which would be 
greater the smaller the transmis.sion coefficient, and the mixing process 
tend.s to reduce the gradient by transferring heat from warm to cooler 
layers. That is, the rate at which heat is supplied to a given layer is 
equal to that due to direct absorption of radiation plus the amount 
due to the alternating vertical circulation of the water. But the rate 
of gain of heat was assumed in the theory to be due entirely to the 
absorption of radiation ; and therefore the estimate of the value of the 
transmission coefHeient deduced from observed temperatures at dif- 
ferent depths would be larger than the true value. This conclusion is 
confirmed by the following computation, based on temperature observa- 
tions near San Diego (McEwen, 1916, pi. 26). The general equation 
(22) (p. 344), is of the form 

e = R^e-''^'i'-^' [cos {at — e) — l] +E„ 

where E^ and E„ are con.stants, for a given latitude. Therefore, 
^^g-6i(6-3) equals the half range of temperature at the surface, 
^^g-6i(io-3) eqi^als the half range at the depth of 10 meters and 
[Eje-^'i'''-^' — Eje-'^i'"-^'] equals the difference between the mean 
annual temperature at the surface and at the depth of 10 meters. If 
there is a vertical flow (p. 374) the general temperature equation 
reduces to the same form (equation 155. p. 390), and can therefore be 
applied to temperatures in the San Diego region. 

Substituting the observed average values of these quantities 
(McEwen, 1916, pi. 26) gives 

jj^g-sii --. 3jg ]jj|]j! range at surface (41) 

2?,e-'''= 2.70 half range at depth of 10 meters (42) 

i?j [c'^^'i — e"''*i]=.40 difference in mean annual tem- 

pei'ature at surface and at 10 meters. (43) 



352 MISCELLANEOUS STUDIES 

From equations (41) and (42) 

e"i= 14^=1.168 or h, = m9 
2.70 

and 

EJe-3ii_c-'''i]=Bi(.1285) = .45 or 7?i = 3.50. 

From equation (43) and the value, 3.5, already found for R^ 

e-si-. — e-'i-i = .1^1^.1142 and &i = .034 

which agrees approximately with the value .039 obtained from the 
first equation. The average value .0365 should be lased instead of the 
large value of /j, exceeding .12 (p. 351), in order to obtain the actual 
rate at which tlie water gains heat as a result of both absorption and 
mixture of water from other layers. That is, the rate of gain of 
heat in the actual sj^stem takes place as if there were no such mixture 
of the water and the coefficient of absorption were less than the true 
value. Hence, as far as the rate of gain and loss of heat is concerned 
we can substitute this more simple ideal sy.stem for the actual one. 
We have now determined all of the constants of the original differential 
equation (4), on page 341, which expresses the time rate of change of 
heat in an element of volume, on the assumption that the average 
flow, either vertically or horizontally, is zero. The modified tempera- 
ture resulting from any additional factor, for example a current, can 
be deduced by solving the above differential equation, to whicli has 
been added the rate of change of heat due to this factor. 

Deditction of the Change in Surface Temperature Produced 
BY A Horizontal Flow op Water 

Preliminary discussion. Statement of assumptions and mathematical 
formidation of the problem. 

It is well known, as stated by a prominent British hydrographer, 
Wharton (1894, pp. 699-712), that "the most obvious phenomenon of 
the ocean is the constant horizontal movement of its surface water, 
which in many parts takes well defined directions." 

The work of both practical seamen and scientists has after many 
years revealed the essential features of the main ocean currents, and 
in a few limited regions a fairly detailed knowledge of the currents 
has been obtained. However, all investigators agree that the esti- 



OCKAX rKMVKnATVRKS 353 

mation of the direction and rate of tlow of water in tlie ocean is 
attended with many difficulties. Some of the metliods of malving snch 
estimates will now be briefly reviewed. 

The most direct and widely used method is the comparison of the 
position of a ship every noon determined from astronomical observa- 
tion and from the log and course during the previoixs twenty-four 
hours. The set of a current estimated in this way is subject to large 
errors, unless special care is taken in making the observations. Under 
ordinary conditions such estimates of currents less than ten miles in 
twenty-four hours are quite uncertain (Kriimmel, 1911, p. 420). 

Another metliod of studying currents is to use drift bottles enclos- 
ing slips of paper on which to enter information as to when and 
where they were found. A sufficient number of records of the initial 
and final positions of these bottles and the corresponding time intervals 
will, under favorable conditions, yield information especially as to 
the average direction of the surface drift. This method is be.st 
adapted to small enclosed seas as the bottles may then be easily 
recovered soon after reaching the shores. For the open oceans it is 
not satisfactory. Other floating objects, such as wrecks, icebergs, trees, 
and plankton also furnish some information about the horizontal 
circulation. 

Under favorable conditions the current at a given place can be 
measured directly by means of a current meter or by observing a 
floating object designed to move with the current. In the open ocean 
the difficulty of holding a ship in a reasonably fixed position usually 
renders these methods impracticable. 

Investigations of the causes of ocean cvirrents and their relation 
to these causes provide indirect methods of determining them. Ocean 
currents are directly due to various external forces, the wind or 
friction of a neighboring current, differences in pressure resulting 
from evaporation, precipitation and differences in specific gravity, and 
are modified by the deflecting force due to the earth's rotation and 
by internal friction of the water. Thus, any theory of ocean currents 
capable of yielding even a rough approximation to the quantitative 
relations between the complex system of causes and the resulting 
motion of the water would necessarily be highly complicated. As a 
matter of fact, great difficulties always arise in attempts to establish 
a connection between practical hydrography and theoretical hydro- 
dynamics, and deductions of currents from their causes are quite 
uncertain except in special cases in which the conditions in the ideal 



354 ■ MISCELLANEOUS STUDIES 

problem agree well with those in nature. The application of theory 
to practical problems is rendered especially difficult, first, because of 
lack of knowledge of the frietional resistance to the motion of sea 
water, and, second, because of the uncertainty regarding the current 
produced by a wind of given velocity and direction. 

One of the most important needs now is a comprehensive pro- 
gramme of observations at sea, of the currents themselves and their 
causes, supplemented by attempts to formulate hydrodynamical prob- 
lems whose solution shall be consistent with the observations. ^Mueh 
credit is due to the pioneer investigators, Zoppritz, Mohn, Bjerknes, 
Sandstrom, Ekman, Jacobsen, and others, for their development of 
methods of dealing- with such problems. 

Another important aid to the determination of oceanic circulation 
is found in the fact that a current consists of water particles tending 
to preserve their temperature and salinity as they move along. These 
characters change slowly and thus serve to depict tlie currents some- 
what as do floating objects that are readily identified. 

This part of the paper presents an attempt to develop, along the 
line suggested in the following translation from Kriiimnel (1911, 
p. 439), a method of deducing currents from the temperature dis- 
tribution : 

No simple rule has been formulated for determining currents from tempera- 
ture charts. But it is conceivable if not certain that a systematic investigation 
of the so-called individual temperature changes will give a reliable basis for 
the estimation of currents from temperatures. (We must distiuguish between 
the annual temperature range, corresponding to definite geographical positions, 
and the practically uninvestigated temperature changes which one and the same 
water particle undergoes along the great horizontal current systems. In a 
continuous current, for example, the Gulf Stream, these individual temperature 
changes which must be distinguished from changes at a given position may 
run through the whole range from tropical heat to the freezing point.) The 
problem is, however, very difScult, and a cursory comparison of the current 
charts in the Atlantic as jirepared from the Log Book of the "Seewarte" 
reveals the great complexity of these closely inter-related phenomena. In 
general, in connection with all water motions time is an all important factor. 
Rapid and slow currents behave very differently as regards their heat content, 
and can therefore give rise to widely different types of isotherms. No constant 
angle between stream lines and isotherms can be proposed; the angle can vary 
between 0° and 00°. The most frequent ease is that of stream lines cutting 
the isotherms obliquely. 

In general, the rate of change of heat in an element of volume can 
be expressed by adding to the right-hand member of the differential 
equation (3) the rate of change due to other factors not considered on 



OCEAN TEMPEllATVEKS 



355 



page 339, and the solution of the new e(iuation will give the tem- 
perature under the new conditions. The rate of change of heat due 
to a horizontal flow H of the water can be readily derived as follows : 
consider a rectangular element of volume (fig. 2) of unit length per- 
pendicular to the direction of flow and of breadth dz measured in the 
dire.ction of flow and thickness chj normal to the direction of flow. 



-i 




Fig. 2. 



Then the rate at which heat enters into the element less the rate at 
which it is removed will be 

Haedy ~Ha{e + d6)dy = —HadOdy = —Ha ~ dzdy ( 44 ) 

which is the time rate of change of heat in the element due to the flow 
of water. Multiplying equation (3) by dz to make it apply to the 
element of volume now considered and adding the above expression 
for rate of change of heat gives tlie new equation 

<T~dydz^—Q{\ogcP,)P^(hjdz - haie — dj d.ydz~E,r~ dy dz 



dt 



dz 



(45) 
Dividing through by adydz and .substituting the value of Q and ^, 
from page 341 we have 

^= Be-M[ (a -)_ a,a) cos at + a.r + l]—l-{d—0,)— H^ 
at - .. ^2 

(46) 

which is the same as the temperature equation (10) with the term 



356 MISCELLANEOUS STUDIES 

— n~ — ) added, x is the distance north or south from the latitude 
dz ' 

chosen for reference, z is the distance from the same point measured 
in the direction of flow, making an angle \^ with the x direction ; there- 
fore X equals nz where i/( is measured from the positive (north) direc- 
tion of X, and n equals cos i/'. Making this substitution in equation 
(46) gives 

^=5[(ai-f a,»2) cosa/-|-o.3?(2-fl]e-''i!'— A-(6i — ^J — H^ 
Of " oz 

(47) 
Solution for the case in which the flow is constant. 
To solve equation (47) let 

= 0' jf- 0" -{- ff" 

where 6' is the solution already found (equation 22, p. 344) correspond- 
ing to H^O, 6" a function of y and t only is to be determined, and 
8'" is a general solution of the part left after substituting {6'-\-6"). 
Substituting the value 6' -\- 6" + G'" for 6 in equation (47) we have 

^+^ +^ = B[{a, + a,nz\ cos at -f a,nz + 1]^"^ 

_],(0'+0"+0"'-0^)-H^ H~-H^ (48) 

dz dz dz 

From the definitions of B', 6" and 6'" this equation reduces to 

66" . 66'" ^_j.^._j.ff„_jj^ -H^ (49) 



dt dt dz dz 

which can be broken up into two equations 

^=_A.r-H^ (50) 

dt dz 



and 

dt ' "" ' " dz 



^ + 7,r' + ff^ = 0. (51) 



From equation (22) which gives the value of 6' we have 
de' Ba.,n , Ba:,nf-'"^!'-^^ . , . x n , Ba^ne'"" 

- ■' ' - [cos (a# — e) — 1|-| = 



=,n Ui — K.e-"^'"-^^ [1 — iA^cosat + B.sinat)] | (52) 



OCEAN TEMPERATUBES 357 



where g, /i,, A^ and B^ are constants having the following values : 
Ba., , Ba.e-'"^ _ Ba„ 



^i \/a.- -\- k- ' y/a- -f A;- 

k 
J.1 = — ^ and Bj ^ 



Va" + A'" Va' + ''■'" 

Substituting the above value of- — in equation (50) gives 

03 



-+A-(9" = — H |sf— e-''i<!'-=»A', [1— (^iCOSai+BiSinaO] |n 



(53) 
remembering that A- equals AjP"''''"'^' and for depths between zero and 
six meters the constant value y equals 6 is to be used for ij, while for 
other depths the actual value of the depth is to be used for ij (p. 343). 
H, the horizontal velocity, may be any function of the time, but it 
is assumed to be independent of z and y. Having in mind a numerical 
application to be made later it will be convenient to let 11 equal the 
periodic function of the time 

il = -ffi ( 1 -|- a^ sin a< -f a. cos at) 
where H^, a^ and a, are constants. Equation (53) then becomes the 
oi'dinary linear differential equation of the first order in 6" and / 

^-^ke" = —n,il ^g — K,{^—) [l—(A,COSat + B,Smat)]^ 

X (1 + «4 sin at -\- a- cos at) (o-i) 

Solving by the corresponding standard formula we have 



e" = —e-''t / I ffjH [fif — — 7u(l — AjCosai + BisinaO] 

X [I + a, sin at + a, cos af]c>'' + C I dt (55) 

where C is arbitrary but independent of t and z. Under these con- 
ditions Ce'''' will evidently be included in a general solution of equa- 
tion (51), and will therefore be neglected in the expression for 6". 
Equation (55) can be directly integrated with the aid of well known 
standard forms and the result for II equal to a constant velocity Hj is 

~ l^i^~ V'^^T^J" (a= + A-=) = 

X [2aA- sin at + (A-= — a=) cos at] (56) 



358 MISCELLANEOUS STUDIES 

Equation (51) in wliich n.^{l -\- a^ sin at -\- a -^ cos at) is substituted 
for H becomes 

~ +M'" +-H"i(l + a, sin at + a- cos at) ^ ^^ (57) 

or ■ ' oz 



In the special case where o^ = a,, = the solution is 

0"'=e-'^^f{t-^) (58) 

where / (/ tt~^} ^^ ^^ arbitrary function of U n"^) • ^^^^^ 

solution can be easily verified by substitution in equation (57). 

For a constant velocity H equals 77^, the general solution of 
the differential eciuation (47) is the sum of the three quantities 
6' -j- 6" -\- 6'" already found, and can be put in the form 

.= {^<"- + "-'"^""^'^COs(a^-.)-l]+g^+g+^-^-'"""^ , , ] 



X l'2al{smat+{k-—a-) COSat] i + | e" ^i / (<- ^ ~" j i (59) 

Suppose the relation of the temperature to the time at a given 
position ^„ is known and that there is a constant horizontal velocity 
Hi from that point in any given direction. From equation (59) the 
temperature at any time and at any point along the stream line 
down stream from the point z equals s,, can be found by giving the 

arbitrary function / l<— ^ tt~" ) *^"*'^^ values that when z equals ^o 

6^6' -\- 6" -\- 6'" will equal the observed temperature, wliich is a 
known function of the time at that point. All of the consstants in 
the equation are given on page 347. Tlierefore /(<') being known, 
when t'. the time at the position, z equals z„ is known, the arbitrary 
function is determined. For a time t and a value (z — z^) of the 
distance from Zg the expre.ssion 

f{t-^^) = f{t') (60) 

where (,_^_^o) = (,.) (61) 

since, in general, the function is determined by the values of the 
independent variable / z — z„ \ 



OCEAN TKMVEKATrUES 



359 



Solution for the case in which the flow is a periodic function 

of the time. 

If the flow is the periodic function of the time 

H = E, (1 + a, fi'm at ^ a, cos at) ( 62 ) 

the term 6' (equation 22, p. 344) will be the same as before, but 6" will 
be given by equation' (55) where a^ and a- are retained. The integra- 
tions can be readily performed with the aid of well known standard 
forms and the result is 

' =-T-L(^-^^^TF^r2(?+w^'"=+'^"^^j 



Ba e-''i<"-''i 



a-+ Ir 



COS at - 



\l;-a,~Saka, — 2a-a,] cos 2at 1 (63) 



The solution of equation (57) when a^ and a-, ai-e retained, found 
by Lagrange's method, is 



e"'=e-^*f^ 



I t ■■ cos at -\ — ^'sin at ) 



z 



(64) 



where /j [ ] is an arbitrary function of 



( 



t ■* cos at -\-- sin at ]— Yf 



This solution can be verified by substitution in equation (57), and 
can be readily changed into the more suitable form 

A-(z — Zo) A-(ai cos at — «:, sin aO 



Bi 



s. J 



/ it — - cos at + - sin af J 



(65) 



360 MISCELLANEOUS STUDIES 

which reduces to equation (58) when a^ and a^ equal zero. The 
temperature at any time and place down stream from the position 
where z equals z^ can be found if the relation of the temperature to 
the time is known where 2 equals z„, by giving the arbitrary function 
/■[ ] values such that for z equals z^, 6 = 6' +6" + 6'" will equal 
the observed temperature which is a known function of the time at 
that position. Thus the arbitrary function is determined .since its 
value is known for a series of values of the independent variable 

(f — cos at' -\ — sin ai' ) , using f for the time where 2 equals z^. 
a a / 

For any other value of the time t' and for a distance (2 — 2„) down 
stream 

/[(^_^COSa< + -^sinaf)-^^] 

=f[t'— -^ COH at' +^smat'l, (66) 

l_ a o — I 

where 

= (/'_-^C'OSar + -^siuar). (67) 

\ a a ' 

Solution for the particular case in wliirli the time interval is so small 
that the solar radiation may be assumed to depend 
only on the latitude. 
In certain cases it will be convenient to take a time interval so 
short that the insolation may be regarded as independent of the time 
and the current may be assumed to have a constant velocity from a 
po.sition 2 equals 2„ where the temperature may be assumed constant. 
Under these conditions the temperature at any point distant (2 — 2,,) 
down stream will be independent of the time if sufficient time has 
elapsed for an element of volume of the water passing through tlie 
position 2„ and having the given constatit temperature to move through 
a distance equal to or greater than (2 — z^). For this steady state, 
equation (47) becomes 

B[b.+ b,m]e-''^^''-^^—k(e — 6,)—n, ^ = (68) 

where h^^l -\- a^ cos at.^ 

&3 = a„ cos at^ -\- a^ 



OCEAN riCMVEliATVUES 361 

and fj is the average of the values of t for the beginning and end of 
the time interval. Let $ = 6'-\-d" where 6' is the solution when 
J7, = 0. Then 



Substituting (i9' + (9") inequation (68) gives 



(69) 



^^r = -f- (70) 

dz H, dz 

For 6' use the normal value determined from the expression j | 

of equation (59) for t^t^ then for surface temperatures using the 
value 6 for y (see page 343) 

66' Ba.,n , Ba„nc-^^^ , . s l^^\ 

T~ = —r — I — cos (at, — e) = g, (<1) 

where tan t ^^t- 

This is consistent with equation (fiO) since 6^ may be any function of z. 
Equation (70) then becomes 

f::+^r=-., (71) 

Integrating equation (71) gives 

e" = ec-^^-a, --^^ (72) 

where 6 is arbitrary. Adding the two solutions 6' and 6" gives 

+ {^.-^?^--^} (73) 

where the expression \ [ is the normal temperature. To deter- 

mine the temperature at a given position, distant (z — z„) from the 
initial position ^i,, give 6 such a value that the expression for 6 in 
equation (73) will reduce to the given temperature when z = z„. Then 
substitute this value and the given value of z in equation (73). 



362 MISCELLANEOUS STUDIES 

Consider two parallel stream lines, A and B, the velocity being 
Ha along the first and i^B along the second, then the temperature in 
A for any value of z minus the temperature in B for the same value 
of z is 

ej,—eB=eAO- ha —Obc- bb +|'(i7B— 5"a)=a9 (74) 

Denote 77a— Fb by AH. tlien 

Ae = —-~AE+eAe-nB+AH —due- hb (75) 

Also if -=^-is small we liave approximately 
-cia 

(76) 



The Rate of Horizontal Flow in the North Pacific off the 
California Coast from Lat. 40° N to 30° N and in the North 
Atlantic off the West Coast of Africa from Lat. 30° N to 
20° N. 

The rate of flow deduced from surface temperatures. 

From the hydrographic cliarts (Thorade, 1909) of the region of 
the Pacific off North America, it appears that that the average direc- 
tion of the surface drift from Cape Mendocino, Lat. 40° N, does not 
at any season differ greatly from a straight line determined by the 
points. Lat. 40° N, Long. 124° W. and Lat. 30° N, Long. 126° W. 
Assuming that there is a surface drift in thi.s constant average direc- 
tion which i.s proportional to the average wind velocity over this 
course, will some numerical value of the drift account for the monthl.y 
temperatures at the down-stream end of the line? From the 
monthly isotherms worked out by Thorade (1909), the observed 
mean monthly temperatures at any point of the region can be found. 
From these observed monthly temperatures at the upper end of the 
line and a mean valuQ of the drift velocity determined by trial, the 
temperatures at the down-stream end will be computed according to 
the theory on page 359. A comparison of these theoretical tempera- 
tures with the observed ones and of this theoretical value of the drift 
with estimates made in other ways will indicate the practical value of 
the theory. The observed temperatures taken from Thorade 's chart 
(1909), and the numerical values of the other cpiantities computed 



Table 4 

Computation of temperatures alonq a horizontal stream-line in the northeastern Fa 

Z = Z„^ 1 



Month = t 




1 


2 




Observed temperature = 6* 




11.3 


10 7 


1( 


Normal temperature ^ 6' 




10 14 


9 OG 


c 


6" (from equation 63) 




-3.38 


-3 38 


■ — >' 


$•" = ^ — ( (9' + e" ) = e- a *"* "' "''" "'• "'" "' 


^f{f' — ^COSar+%mal') 
a a 


4.54 


5 02 


4 


- (a* cos at' — as sin a(') 23 sin at' 

e-a — e 




.887 


.819 




f, f, .23 sin al' 

*f ( V— %os at' +%m at') = e 0'" 

a a 




5.11 


6 14 


e 


*f — -'cos at' + ^sin at'=t'— 1.15 sin at' 

a a 




-.42 


1.0 


1 



: = 



Normal temperature ^ 0' 


18.7 


18.0 


18 


e' + 6" 


15.32 


14 62 


14 


{t —-'cos at + -'sin at)--^^ =[i~ 1-15 sin at — 8.85 

a a Hi \_ _ 


-8.77 


-7.35 


-6 


f (t ^COSa< + — .sm an— 

•' L ^ a 'a Hi _ 


4.5 


2 4 


1 


-^ — («! COS at — Or. sin aO -i on _:_ .23 sin at 


.167 


.154 




e"'=:.188e- -^Ssinafy.^ -j 


.8 


.4 




0' 4- (9" + 6"' = 61 = the computed temperature 


16.1 


15 


14 


Observed temperature 


16.7 


16 5 


16 


Computed minus observed temperature 


-0.6 


-1.5 


-1 




t' = 


-9 
6.27 


-8 


* These two lines are continued here for negative values of t' 


4 






-10.15 


-9 



Tablb 4 
Computation of temperatures along a horizontal streamline in the northeastern Pacific, where the 



current varies penodically with the time 



Month = t 



Observed temperature = 6 
Normal temperature = 0' 
g" (from equation 63) 

.,,, /) la' -i—A"\ -,-- (Oi cos aC — Or, sin of) » / ., 0,^ #• . '^s • ii\ 



- (04 cos at' — Ob sin at') __ 23 sin at' 



ro 



*' "'\ 



a, . 



.23 sin at' 



*f(f— %os at' +-'sin at') = e 6" 

> ^ a a 



*f_-%os at' + ^sin at'=t'— 1.15 sin at' 



Normal temperatiire = 6' 



' + ' 



lt-'%osat + -'sin at)-— ^= r< — 1.15 sin ai — 8.35l 

a a Hi L_ _| 

y[^(i_%OSa<+JsinaO-^] 

— ^-= (at cos at — Od sin at) < qq .:_ .23 sm at 

6 ill n — .J-oo e 



r=.188e- •''''"'"/I ] 



e' -(- 61" + e"' = 61 = the computed temperature 



Observed temperature 

Computed minus observed temperature 



* These two lines are continued here for negative values of f 




13.1 


12.4 


14.9 


12.27 


-3.85 


-3.61 


-2.05 


3 48 


1.127 


1.00 


1.82 


3.48 


11.58 


12.0 



= 



18.7 
15.32 
-8.77 
4.5 
.167 



18.0 

14.62 

-7.35 



2.4 1.5 



18.2 
14.59 
-6.5 



19.2 



15.35 



-5.35 



.154 



16.1 



16.7 



-0.6 



t' = 



15.0 



16.5 



-1.5 



,149 



.1 



14.8 



16.2 



-1.4 



20.8 



16.21 



-3.93 



154 . 167 



.10 



15.4 



16 1 



-0 7 



6.27 



-10.15 



4.82 



-9.0 



2.58 



-7.58 



22.6 



17.77 



-2.35 



-.75 



.188 



05 .14 



16.2 



16.3 



-0.1 



-6 
1.10 
-6.0 



17.6 



17.0 



+0.6 



.18 

-4.42 



23.9 



18.84 



■1.2 



212 



.35 



19 1 



18 3 



-1-0.8 



-4 



-1 70 



-3 



24.6 



19.54 



.65 



5.3 



.230 



12 



20.7 



18 9 



-t-1.8 



-3 



-1 62 



-1.85 



24 4 



19 57 



1.8 



6.3 



,236 



15 



21.1 



19.4 



+1,7 



-2 



23.3 



18.71 



2 66 



5 7 



.230 



1.3 



21 6 



17.75 



3 23 



4.4 



20.0 



16.39 



3.65 



4.0 



.212 



.93 



20.0 18.7 



18.9 



+ 1.1 



-1 



.89 



■1.0 



1.82 



-.42 



18.2 



.188 



17.2 



17.2 



+0.5 0.0 



3.48 



cific, where the current varies periodically with the time 



3 


4 


5 


6 


7 


8 


9 


10 


11 


12 


1.7 


11 


11.0 


12 2 


13.2 


12.0 


12.0 


13.8 


13.1 


12.4 


1.34 


10.9 


13.3 


15.93 


18.06 


19 14 


18.86 


17.3 


14.9 


12.27 


;.6l 


-3.85 


-4.59 


-4.83 


-5.06 


-5.06 


-4.83 


-4.59 


-3.85 


-3.61 


-.97 


3.95 


2 29 


1.10 


20 


-2.08 


-2.03 


-1.09 


-2 05 


3.48 


794 


.819 


.887 


1.00 


1.127 


1.221 


1 259 


1.221 


1.127 


1.00 


..27 


4.82 


2.58 


1 10 


.18 


-1.70 


-1 62 


.89 


1.82 


3.48 


85 


3.0 


4.42 


6.0 


7.58 


9 


10 15 


11.0 


11.58 


12.0 



.2 


19.2 


20.8 


22.6 


23.9 


24.6 


24.4 


23.3 


21 6 


20.0 


.59 


15 35 


16 21 


17.77 


18.84 


19.54 


19.57 


18.71 


17 75 


16.39 


.5 


-5 35 


-3.93 


-2 35 


— .77 


.65 


1.8 


2.65 


3.23 


3.65 


.5 


-.8 


-.3 


-.75 


-1.2 


5.3 


6.3 


5.7 


4.4 


4.0 


.149 


154 


.167 


.188 


.212 


.230 


236 


.230 


.212 


.188 


1 


.10 


-.05 


.14 


.35 


1.2 


1.5 


13 


.93 


.8 


.8 


15.4 


16.2 


17,6 


19 1 


20.7 


21.1 


20.0 


18.7 


17.2 


.2 


16 1 


16.3 


17.0 


18.3 


18.9 


19.4 


18,9 


18 2 


17.2 


.4 


-0 7 


-0.1 


+0.6 


+0.8 


+ 1.8 


+ 1.7 


+ 1.1 


+0.5 


0.0 




-7 


-6 


-5 


-4 


-3 


-2 


-1 







.82 


2 58 


1.10 


.18 


-1.70 


-1 62 


.89 


1.82 


3.48 







-7.58 


-6.0 


-4.42 


-3.0 


-1.85 


-1.0 


- 42 








OCEAX TEMPEliATVRES 363 

from the theory (pp. 355-360) are eondensed in table 4, iji which 
the following values of the constants are nsed: «4^0, a.^ = — .6, 
«!==— .318, a, = —.0244, a, = —.0166, 7i = .20, and ir = — 1.2 
(1 — .6 cos 30° equals the drift, in degrees per month equals 
1.(1 to 3.8 miles in twenty-four liours. The mean wind velocity in miles 
per hour over the cour.se considered (Mooi-e, 1908-11) is approximately 
F = 10[l — .6cos (300°]. 

Tlic rate of flow deduced from temperature data compared icith that 
expected from the empirical relation of winds to currents and ivith 
direct ohservations on currents. 

As stated by Helland-Hansen in his paper on physical oceanography 

(:Murray and Hjort, 1912, p. 247) : 

The wind may produce a current, particularly in the surface layers, thus 
altering the direction and velocity of the existin<f current. We know very 
little, however, about the relation between wind and current, through lack of 
detailed observations, although the question is naturally of the first importance 
from an oceanographical point of view, as well as from its bearings on the 
conditions of everyday life. This is one of the principal tasks for the ocean- 
ographer of the future; such observations are difficult to make, no doubt, but 
with modern methods much can be done. 

However, numerous ohservations of winds and currents have been 
made. And, although the relation of wind and current varies with 
the wind velocity, the latitude, coast line, depth, and distribution of 
specific gravity, some progress has been made in estimating the drift 
that a given wind velocity will produce. A careful investigation of 
this question based on Ekman's theory (1905, 1906) and a large mass 
of available data made by Thorade (1914) yielded the following 
results. In case the coast is sufficiently distant and the effect of the 
pi"es.sure gradient due to differences in specific gravity is small, the 
drift will be directed at an angle of 45° to the right of the wind 
direction in the northern hemisphere. The relation of the drift to the 
wind velocity estimated by Thorade (1914, p. 387) is 

„ .0259\/V -- ..meters „ ^ . mi. ,^^, 

H= ^ , I <4.3 <8.74t (77) 

Vsin<> sec. hour 

and 

^_m26y 5 meters ^^^mi^ 

Vsin</> sec. hour 

where V is the wind velocity. 27 is the current in meters per second, 
and (f> is the latitude. 



364 



MISCELLANEOUS STVDIES 



The mean latitude of the drift eompTited from temperature data 
(p. 362) is 35° and its direction was 45° to the right of the mean wind 
velocity in accordance with Ekman's theory (1906) and Thorade's 
estimate from observations (1914). From equation (78) and the 
observed value of "T (p. 363) the drift would be 3.9 miles in twenty- 
four hours if it were due entirel.y to the observed wind.s, uninfluenced 
by the coast and differences in specific gravity. This estimate is of the 
same order as 2.4. that made from temperature observations (p. 363). 
Again, direct observations of the drift having a southerly component 
(Thorade. 1914, p. 283) near the head of the stream, Lat. 40° N to 
50° N, gave the values presented in table 5. 

T.\BLE 5 
Observed surface drift, and values computed from temperature data 



Month 


4 


5 


10 


Mean 


Observed drift in 24 hours 


3.69 


2,0.5 


2.41 


2.6 






No. of observations 


21 


24 


54 








Computed drift in 24 hours 


3.12 


3.6.5 


1.68 


2.8 



Thus the theoretical drift estimated from temperature data agrees 
as well with the observations as could be expected. And it appears 
from the comparisons made that estimates of the drift from tempera- 
ture data will prove to be as reliable as those made by other methods. 



The surface current during a short time interval near the northivest 
coast of Africa, estimated from surface temperatures, and com- 
pared, irith direct observations, and with results deduced from the 
empirically ascertained relation of udnds to currents. 

From a series of direct measurements by means of a float designed 
especially for the purpose (Schott et al., 1914), the average flow 
between latitudes 20° N and 28° N, off the west coast of Africa, was 
found to be nearly parallel to the coast and toward the southwest. 
These current measurements were accompanied by observations of 
surface temperatures and winds, and the stations were distributed 
along a line nearly parallel to the average surface drift and about 
150 miles offshore. All of the observations were made during the 



OCEAN TEMPESATUllES 365 

short time interval from June 2 to June 15, 1911, and are therefore 
appropriate for the application of the theory developed on pages 360- 
362 for estimating surface currents from temperatures. 

The mean position during the three days, June 2, 3, and 12, was 
Lat 30° N, Long. 14?6 W, and that during the three days, June 13, 
14, and 15, was Lat. 24° N, Long. 17?3 W. The distance between these 
positions is 6.74, the unit being a degree of latitude, and the mean 
surface temperatures were respectively 18?32 and 19?12, each value 
being the average of eighteen observations. In equation (73), page 
361, (z — Z(,) is the distance, measured in degrees of latitude in the 
direction of the drift, and the initial position is in this case at Lat. 
30° N. The direction of the drift was found to be to the south at an 
angle of about 27° to the right (west) of the meridian, therefore the 
change in latitude corresponding to the distance {z — z^) along the 
line of the flow is (cos27°) (z — z^) ^ .891 (z — z^) . From these 
values and the numerical values of the constants given on page 346, 
equation (73) becomes 

^ = 22.6— (.891) (.41) (2 — So)+^e '" h' '" +(.891) (1.88FJ 

which gives the temperature at any point along the stream line, the 
mean velocity being H^ degrees per month. 

To determine Hj substitute the two mean temperatures with the 
corresponding values of {z — z^), thus obtaining two equations 

18.32 :== - 22.6 +1 + 1.685fl^i 
and 

_ 1.461 

19.12 = 22.6+ (.365) (6.74) -\- de^ir+l.&SbE^ 
Eliminating 6 gives the equation 

1.461 

— (4.28 + 1.685ff,)f~"ffr+ 1.68577, = — 5.94 

from which the value of 77,, found by trial is 

77, = — 9.4 degrees per month = — .78 miles per hour. 

Using this value of 77, the theoretical temperature at any point along 
the stream line is 

„ „^ .,„_ , , ,, ^ .0231(2 — z„) 

6 = 6./o — .36o {z — Zq) + ll.o7e 

where (z — z„) is negative since the latitude decreases in the down- 
stream direction. 



366 



MISCELLANEOUS STUDIES 



Direct estimates of the drift were made at six stations along this 
line from angular measurements relative to a float, the ship being 
manoeuvered in such a way as to keep the sounding cable as nearly 
vertical as possible. The values obtained at each station in the order 
from north to south are 1.0, 0.7, 0.9, 0.8, 0.9, 1.3 miles per hour in a 
southwesterly direction. Each value is the mean of about twenty-five 




Pig. 3. Geometrical construction for determining 
the surface current jiroduced by wind. 



the effect of a coast oii 



observations. The components parallel to a line from the first to the 
last station having the mean direction of the observed drift are 0.99, 
0.7, 0.9, 0.7, 0.86, and 1.11 miles per hour, and the mean value is 0.88. 

From the four estimates based on "dead reckoning" and the 
position of the ship determined from astronomical observations at 
noon, the drift appeared to be directed to the west of the direction 
determined by the "float" method. The values are 0.4, 0.5, 0.4, 0.4 
and the components parallel to the mean direction of the drift found 
by the float method are 0.3, 0.2, 0.16, 0.19, the mean value is 0.21. 

The wind blew steadily from the northeast, the observed velocities 
in miles per hour being 28, 23, 28, 34, 3, 18, 13, 28, 28, 28, 34, and 34; 
the mean is 25. 

From equation (78), page 363, using 24°, the mean latitude of the 
stream line for <^, the drift due to a wind velocity of V miles per hour 
would be .01975F miles per hour. Using the value 25 for V the un- 



OCEAN TEMPERA TVHES 



36T 



disturbed drift due to the wind would be 0.494 directed at an angle 
of 45° to the right of the wind direction; this direction of drift is 
nearly the same as that obtained from dead reckoning. If the .same 
wind velocity prevailed over the whole coastal belt, a correction to 
the above estimate of the drift must be made (Ekman, 1906, p. 23). 
Tile computation can be carried out graphically as follows (fig. 3). 
Let OT be the direction of the wind, and OA represent in magnitude 
and direction the "undisturbed drift" computed from equation (78). 
If a circle is described through A tangent to OT, and a line AD is 
drawn parallel to the coast then OD will represent in magnitude and 
direction the corrected surface drift. In the ca.se imder consideration 
the corrected estimate OD is twice the value of OA and makes an angle 
of about 27° to the right (west) of the observed mean direction. 
Therefore the component parallel to this observed direction is 
(0J9) cos 27° == 0.89 (0Z)) = (0.89) 2 (0A)=: 1.78 (0.4). 
The results corresponding to various values of the wind (T) are 
presented in the following list. 



V 


OA 


OD 


(OD) co,s 27 


1.3 


.257 


.51 


.46 


18 


.356 


.71 


.63 


25 


.494 


.99 


.88 


34 


.672 


1.34 


1.20 



Finally it is evident that the velocity of 0.78 miles per hour 
deduced from surface temperatures agrees well with the estimates 
made bv the other methods. 



The Rel.\tion of Temperature to Time, Depth and Rate of 
Vertical Flow in the Interval from 40 to 600 IMeters 

Statement of assumptions and mathematical formulation of the 

problem. 

It has been found (p. 351) that the direct heating of the sea water by 
the absorption of solar radiation is proportional to e"*'" where 6, > .12 
and jj is the depth in meters. Hence at the depth exceeding 40 meters 
this direct heating effect would be less than 1 per cent of that at the 
surface. Also the temperature range at that depth woidd bear the 
same proportion to that at the .surface if the variation in rate of 
gain of heat were due only to the variation in this rate of absorption. 



368 MISCELLANEOUS STUDIES 

However, observation shows that there is a seasonal variation of 5° 
at 40 meters and exceeding 1° at 100 meters (Murray, 1898, p. 127; 
MeEwen, 1916, p. 268) ; thus something other than the direct absorp- 
tion of solar radiation must be the main factor in heating the water 
of these lower levels. 

These facts show that there must be a transfer of heat between 
the upper and lower level, but the ordinary process of heat conduc- 
tivity, as illustrated by laboratory experiments on still water, is 
wholly inadequate to effect this transfer at a sufficiently rapid rate 
(Wegemann, 1905a, 1905Z)). It is now generally recognized that this 
transfer of heat results from an alternating vertical (p. 338) circula- 
tion of the water (Helland-Hansen, 1911-12, pp. 68, 69), in which at 
any given instant certain portions of the water are moving upward 
while otliers are moving downward. The resultant flow of a given 
column of water may be either upward or downward, or may be zero. 
"Without analyzing the complicated process by which heat is trans- 
ferred from one level to another in the ocean, it will be assumed to 
be similar to ordinary conduction. But the coefficient of conductivity 
corresponding to conditions in tlie ocean will depend mainly on the 
intensity of the circulation or mixing process (Gehrke, 1910, p. 68; 
Jacobsen, 1913, p. 71), and might be called the "coefficient of con- 
vective conductivity" to distinguish it from the ordinary laboratory 
coefficient. In the following investigation this coefficient of conduc- 
tivity will be used and the direct effect of solar radiation will be 
neglected. If the resultant vertical flow is zero, the well known partial 
differential equation 

-^=.= ^ (79) 

applies, where is the temperature, t is the time, y is the distance 
below the surface, and p.- is the diffusivity, a constant proportional 
to conductivity. If the resultant vertical flow is w it follows, as on 
pages 354-355 that the time rate of change of temperature due to this 

flow is { — -iv ——) and the temperature equation then becomes 
\ oy ' 

d6 „ d-d 66 ,Q^^ 

— =/x- -— r — M'-T- (80) 

dt '^ dy- dy 

Equation (80) is a special case of the general equation of the conduc- 
tivity in a moving medium (Winkelmann, 1906, p. 444). Equation 
(79), a special case of Pourtier's equation of the flow of heat in a 



OCEAN TEMPER ATUEES 369 

stationary medium, has been applied to the problem of temperature 
distribution in the ocean by Wegemann (1905a, 19056), using the 
laboratory value of ju,-, but the theoretical results were of an entirely 
different order of magnitude from those given by observation. 

Jaeobsen (1913, p. 71) has successfully applied the equation of 
the form (79) to some data on the distribution of salinity and cur- 
rents in the sea near Denmark. He determined fr, the Mischungs- 
intensitat from field observations, using the idea that salt content, 
quantity of motion, temperature, and other properties of sea water 
varj^ because of the alternating changes in the position of the water 
particles. The writer is, however, not aware of any application of 
equation (80) to ocean ographic problems. 

Solution for the case in rchich the vertical flow is constant. 

If the vertical velocity has the constant value ii\ then we have 
(p. 368) to find a solution of the following linear partial differential 
equation with constant coefficients 

69 .6^6 . 66 . .„,, 

-TT— /i--T-:r+«'i-T— =0 (81) 

6t 6y- 6y 

satisfying certain bovmdary conditions. To determine the temperature 
at any depth, having given that at the upper level y = y.. we must 
have a solution reducing to the given function of the time t (in this 
paper it will be a periodic function of at the upper level and having 
a given constant value at the lower boundary. A convenient method 
of solution is to assume 

e = Me<'v+^* (82) 

and substitute in equation (81). The result is 

l)-\-iv^a — /x-a-^0. (83) 

Therefore 6°^'+'" is a solution of equation (81) for all values of the 
constant M and for all values of a and 6 satisfying equation (83). Let 

a^di ± hj, (84) 

where a^ and h^ are real, then from equation (83) we have 

h^[l>.-{a^'—h^-) — u\a,] ± [(2a,/i= — wj&ji (85) 



370 MISCELLANEOUS STUDIES 

and, if the solution is to be a periodic function of the time having 

o 
the period — where a^ is positive 

»i 

/j-'ia^- — &1-) — u\ai = (86) 

{2a,ix- — ii\)h, = a, (87) 

Solving equation (86) for a^ and equation (87) for b^ we have 



and 



w, =p ^/u\^ + 4^'b,- 
Oi= 2~2 ^ ' 



\=7r^ (89) 



Since the temperature and the amplitude of the temperature 
decrease as the depth increases, the exponent o,?/ and hence a, must 
be negative (y is positive in the direction from the upper surface 
downward). Therefore only the negative sign is admissible before the 
radical in equation (88) and 



is definitely determined by given values of n\. /x- and ±&i. Solving 
equation (87) for a^ gives 

therefore because of equation (90) ' ., must be negative, or b^ 

2b,ii- 

must be negative since a^ is assumed to be positive. From equations 
(90) and (91) we have 

„^==Vwr+V^' (92) 

and 



where only the plus sign is admissible since b^" is necessarily positive. 
Substituting this value of &/ in equation (90) gives 



"^~2^^~ 2^=V2- ^^ 



OCKAN ■iKMVElATVEKS 371 

substituting this value of a, in equation (89) gives 

h =: "i _ (95) 

which agrees with the result already found on page 370, that —^^ 
must be negative. From pages 369 and 370, e^Me'"'+^', where 
a^a^±bii and b^ ± 0^= ±{2a^fji." — m'J&i- 

The solution of equation (81) is therefore 

6i = i/e'"2'±('"!'+°i"' (96) 

where M and a^ are arbitrary constants, a^ and h^ are given by equa- 
tions (94) and (95) and the same value of a^ is to be used with either 
the plus or the minus sign before the expression in brackets. From 
the properties of imaginary exponents equation (96) can be put in 
the real periodic form 

e = ("^y { A.shi {b,y + a,t) +B, COS {b,y + aj)] (97) 

where A^, B^ and a^ are arbitrary constants. 

Also since the differential equation is linear the sum of any number 
of such expressions will be a solution. Therefore the following more 
general expression 

n = oo . 

6=^2 e"-" iAnsm {b„tj + aj)+ B„ cos {b„y + a„t) | (98) 
n = 
is a solution, where A„, B„ and a„ are arbitrary constants and a„ and 
b„ have the values 






and 



V2 



K— ^ """ (100) 

— ^w-c + V"'i* + 16ia*a,r 

1 'a~ W 

Denoting — - \/-^ bv A„ and — ' bv X the following approximate 
fx. ^ 2 ■ /i^ ■ 

expression for a„ and bn can be easily derived 

a„=^+(l + /,,r + 7,/)A„ (101) 

&„=(1_7(„=— 7,/)A„ (102) 



372 MISCELLANMOVS STUDIES 



W - 
where hn^=^ —4 — r, is small. If the velocity u\ equals 0, 

a„^bn^^ — ~\"^ ^^'^ equation (98) reduces to the well known 

form 

)l=co 1 , , — ^ 

«^0 



ij^ \] (103) 



A solution independent of the time results, if in equation (83) we 

make h^O and a= — , or b = a^0. The result is 
A*" 

Wi 

e = Ce'''''+D = Ce^i'+D ,(104) 



where C and D are arbitrary constants. This expression for 6 can be 
added to the right-hand member of equation (98), giving the more 
general solution 

(9 = Ce'^''+I> + e'"44,sin {b,ij + aj) + B.cos {b,y + a,t) I (105) 



Solution for the case in which the vertical flow is a periodic 
function of the time. 

If tlie vertical velocity has the value w = iVi[l-\- r cos at] the 
general equation (80) becomes 

^=,= |»-.,,[l + .-™.,l|^ (106) 

Let 

0^gay + fit) (107) 

and substitute in equation (106), the result is 

^^— i^-a- + aw, [1 + r cos at] = (108) 



from which 



f{t) = {iJ.-a-—aw,)t — -^^^-^s\nat + c (109) 



where c is an arbitrary constant. 



OCEAN TEMFKJiArUBES 373 

Let 

a^a^±hii or a= = ai= — bi'±2aj)ii (HO) 

then 

fl = Me"'^ - '''>'' + [/i'(V~''i'± 20,6,0 — «,"',+ 6,i<',i]< — -^^sinaf (HI) 

the arbitrary constant of equation (109) being so chosen, that when 
r equals zero, equation (111) reduces to equation (82) derived for a 
constant velocity. 

Eearranging the terms in the exponent of e in equation (HI) gives 

(112) 

Let 

h,i2f,-a, — u\)=a, (113) 

and 

fj-'ia^- — &1-) — ait(.''i = (114) 

as before (p. 370). Substituting in equation (112) and making use of 
the properties of imaginary exponents gives 

^(ga,y—^^ sin alj j ^i siu la,f + b^tj ^—^ siu a< j 

+ Bcos(a,f + 6,y-^i^sina/)| (115) 

wliere a, and &, have the values given on page 370 and A^, B^ and a^ 
are arbitrary. The values 

&j = ai = and «! = or A 

are also consistent with equations (113) and (114) and lead to the 
solution 



(7eX!'+ Z) — C (1 — e-^"*'" "') e 



\v 



where C and D are arbitrary constants and A has the value — ^. 



374 MISCELLANEOUS STUDIES 

The differential equation being linear, this solution can be added to 
the right-hand member of equation (115) giving the solution 

_"i«'i'' , { A ■ r i , 7 b,w,r . ^~| 
_j_ gaii/ ^^"1"' j .4isni aj+h^u i-^-smaf 

-|-BiCOS aj-^b^y — ^sina< I 

= Ce^vJ^D + I 4, sin ^aj + &i(/ — ^i^^sin at~\ 

+ B, cosfa,^ + b,y _i^i!^ sin atl [ -(l — f"^ ■*'" A 

I Ce^!' + ?"■!'( J, sin a,t-{-b^y i^^sin af 



4- Bi cos 



a,f + &,y— ^^i^sina/l") I (116) 

which reduces to equation (105) corresponding to a constant velocity 

when r^O. If the product of A. «i or /j, by f-^-sina* j is small 

equation (116) can be transformed into the following apjiroximate 
form, i-etaining only the first powers of the small quantities. 

e = C gX!/ + Z) — C ('^^^sin aA c ^'J 
+ e'''viA,s'miaJ.-\-b,y) + S, cos {aj + b,y)+^r {B,b, — A,a,) 

f cos (a — a J — ?),,(/) — cos (a + a,f + b^y) j — (Bi«i + ^i&J 

( sin (a + aj^ + ^1^) +sin (a aj — b^y) \ i (117) 

Numerical values of the constants in the solution, determined from 
temperature observations in the Pacific near San Diego. 

It is well known that the waters of certain inshore regions, includ- 
ing that off the west coast of North America, have a temperature 
significantly below the normal for the latitude. Various explanations 
of this phenomena off the California coast have been offered, but 
(Holway. 1905, and McEwen. 1912, 1914, 1916) the only one .so far 
proposed that is consistent with all of the known facts is that of an 
upward flow of cold water from lower levels. 



OCEAN TEMPESATVRES 



375 



Assuming this upward flow to be the only cause of the temperature 

reduction, the theory developed on pages 372-374 will now be applied 

to the series of temperature observations made off the Coronado Island 

about twenty miles from San Diego (McEwen, 1916, pp. 267, 268 and 

pi. 26). It follows from Ekman's theory (p. 401) that the vertical 

velocity off the California coast is proportional to the component of 

the wind velocity parallel to the coast, and decreases in magnitude as 

the distance from the coast increases. For this rea.son the velocitj' 

estimated from the temperature data mentioned above will be less 

than that nearer the coast. 

Table 6 

Average of observed and computed monthly temperatures of San Diego 

at a series of depths. 



Month 


1 


2 


3 


4 


5 


6 


7 


8 


9 


10 


11 


12 


mean 






Depth in meters 

































15.0 


14,3 


14.6 


15,2 


16,1 


17.8 


19,7 


20,6 


20,2 


18,8 


16.8 


15,5 


17,0 





C 






























O 


15.0 


14.6 


14.5 


14.7 


15,4 


16,6 


18,2 


19.5 


19,9 


18,8 


16,8 


15,4 


16,6 


10 


C 

































14.2 


14.2 


14.0 


13,6 


13,0 


14,2 


15,0 


16,0 


18,2 


19,0 


16,2 


15,0 


15,2 


20 


C 

































13.8 


13.8 


13.5 


12,6 


11,0 


12,2 


13,0 


14,0 


17,8 


18,0 


15,8 


14,5 


14,2 


30 


C 

































13.4 


13.4 


13.0 


11 


10 5 


10,8 


11,8 


12,7 


14,8 


16,8 


15 4 


14,0 


13,1 


40 


C 


13.4 


11.9 


10.6 


9,9 


9,9 


10,6 


11 9 


13,4 


14,7 


15,5 


15,5 


14,7 






O 


13 1 


13.0 


12,3 


10 5 


10 


10,5 


11 


12,0 


13,6 


15,0 


15 1 


13,5 


12,5 


50 


C 


13.2 


11.9 


10 6 


9,8 


9,8 


10,4 


11,6 


12,9 


14,2 


14,9 


15,0 


14,4 









12. S 


12 6 


11.7 


10,0 


9 9 


10,2 


10,7 


11,0 


12,8 


14 3 


14 7 


13 2 


12 


60 


C 


13.1 


US 


10.6 


9,9 


9,7 


10,2 


11,2 


12,5 


13,7 


14,4 


14,6 


14,1 









12.4 


12 1 


11 


9,9 


9,8 


10,0 


10,5 


10 8 


12,2 


13,8 


14,1 


12,9 


11,6 


70 


c 


12.9 


11.7 


10.6 


9,8 


9,6 


10 


10 9 


12,0 


13,2 


13,9 


14 2 


13,8 









12.0 


11.7 


10.7 


9,8 


9,7 


9,8 


10,3 


10,7 


11,8 


13,0 


13,7 


12,7 


11 3 


80 


c 


12.7 


11.6 


10.6 


9,8 


9,5 


9,8 


10,6 


11,6 


12,7 


13,5 


13,7 


13,4 









11.7 


11.3 


10 3 


9,6 


9,6 


9,8 


10 2 


10 5 


11 2 


12,8 


13,2 


12,3 


11 


90 


c 


12.5 


11 5 


10 5 


9,8 


9,5 


9,7 


10,3 


11 3 


12,3 


13,0 


13,3 


13,1 









11.3 


11,0 


10.0 


9,5 


9,5 


9.7 


10,0 


10,3 


11,0 


12,4 


12,8 


11,9 


10,8 


100 


c 


12.2 


11.4 


10 4 


9,7 


9,4 


9,5 


10,1 


10,9 


11,9 


12,6 


13,0 


12,8 






o 


10.3 


9.9 


9 2 


9 


9 


9,2 


9,5 


9,8 


10 2 


10 9 


11 


10,7 


9,9 


150 


c 


11.2 


10.7 


10 


9,4 


9,0 


8,9 


9,1 


9,6 


10 2 


10,9 


11,3 


11,4 









9.5 


9,0 


8.8 


8,7 


8,8 


8.9 


9,1 


9,4 


9,7 


10,2 


10,4 


10,0 


9,4 


200 


c 


10.1 


9.9 


9.5 


9,1 


8,7 


8,5 


8,5 


8.7 


9.1 


9,6 


10,0 


10,2 









8.4 


8.1 


8.3 


8,2 


8,2 


8.2 


8,4 


8.7 


9,0 


9,4 


9,4 


8,7 


8,6 


300 


c 


8.5 


8.5 


8.4 


8,2 


8,0 


7,8 


7,7 


7.7 


7,8 


8,0 


8,2 


8,4 









7.8 


7.7 


7,6 


7,5 


7,6 


7,6 


7,7 


7,8 


8,0 


8,4 


8,4 


7,8 


7,8 


400 


c 




7.4 


7.5 


7.5 


7,5 


7,4 


7,2 


7,1 


7,0 


7,0 


7.1 


7,2 


7,3 


7,0 


500 


c 


6.8 


6.8 


6.8 


6,8 


6,7 


6,7 


6,7 


6,6 


6 6 


6 6 


6,7 


6,7 





376 



MISCELLANEOUS STUDIES 



From table 6, which gives the observed temperature averages at 
different depths and months, the constants of ecjuation (116) or the 
simpler approximate form equation (117) will now be determined. 
The mean annual temperature (9„, is given by the first two terms 



which can be put in the linear form 

'Logc{0,n — D)=hogcC + Xij. 



(118) 



(119) 



Assuming different values of D, plotting the results, and selecting the 
value of D, for which the points fell most nearly on a straight line, 
resulted in the following values of the con.stants: 



Z) = 5.6, 



or 



C = 8.3, X = 
: 5.6 + 8.3 e-""*" 



-.004 



(120) 



where y is the depth in meters. 

The satisfactory agreement between the computed and observed 
values of 6„„ shown by table 7, proves that the form of the function 
deduced from theory differs but little from the true form. 

Table 7 
Computed and ohserved mean annual temperatures at a series of depths from 

40 to 700 meters 



Depth 


40 


50 


60 


70 


80 


90 


100 


150 


200 


300 


400 


500 


600 


700 


Om computed 
^mob.served. 
Difference... 


12°7 
13.1 
-.4 


12°4 
12.5 
- 1 


12?1 
12.0 

+ .1 


11?9 
11.6 

+ .3 


11°6 
11.3 

+ .3 


11?4 
11.0 

+ .4 


11?2 
10.8 

+ .4 


10^2 
9.9 

+ .3 


9?3 
9.4 
-.1 


8?1 
8.6 
-.5 


7?3 
7.8 
-.5 


6?7 
7.0 
-.3 


6?4 
6.3 

+ .1 


6°0 
5.5 

+ .5 



The time of minimum wind velocity is in December, that of the 
maximum is in July (McEwen, 1912, p. 265), and the magnitude of 
the wind velocity, and therefore the vertical velocity of the water, 

is approximately proportional to 1 + r cos — where t = 12 corre- 
sponds to the time halfway between Jime and July and r = 0.2. 
Also since, as showii by table 6, the temperatures have the same period 

as the wind, o, = a = - in equation (117). In order to determine 
6 

the remaining constants substract from the observed temperature for 



OCEAN TEMPEEATVUES 377 

each month and depth the observed mean annual temperature for 
that depth. Then subtract the expression 



from each of these values using a provisional value of u\. Then fit 

Me"^" cos {at + b,lj — e) 
the equivalent of the expression 

e°i!')4isin {at + &iy)+B, cos {at + bji) - 



(p. 374) to these remainders, thus determining M, e'. a^ and h^. 
The last part of equation (117) is neglected at first and its value 

estimated later. Assuming w, to be — 31 -^ the espres.sion 

month 



■ C ^"^ '' (sin aOe'^" becomes — .38 ( sin -^ je' 
The following formulae corresponding to the special case when 
a:=ai= — are useful in determining a^, &i, w^ and /*-, and follow 

from equations (89, 91, 94 and 95) remembering that A= —^. 
J41 .524 _ .524 

(121) 

"•■■'''' ,^h = ,r^^ (122) 



{X^y = ^, J^. ^ (123) 



_\Mf^'i>.)r-) ^i 



«! can readily be determined from the rate at which the annual 
range varies with the depth. A was determined from the mean annual 
temperature at different depths. These values substituted in equation 
(122) give firbi from which n" and h^ can be found by substituting 
in equations (123) and (122), and finally the product kfx- gives the 
velocity tt'i.* 



* If \ and fc, are given, the following equations derived from equations 90 
and 95 can be used for computing the remaining quantities: 

— a, — Xa, 



"b,V(2b.)-' + X'' ' 6.VT26,)' + X=' ' 2 2 



, a,=;.-5V(26,r + X' 



378 MISCELLANEOUS STUDIES 

The constants obtained in this way are listed below : 

A =—.004. a^ = — .008, ^- = 7760, ?)i = — .00560, «■ =— 31 E?!££5 

month 

A,= — —-*/ — =— -0058, .¥ = 4.40, e' = — 6r. 
M > 12 

Assuming t = 1 for January, and using the same origin for 
determining the time in the expression for wind velocities, the expres- 
sion for the temperature becomes 

^ = 5.6 + S.Se-""*" + 4.4e— "^J- cos (SOt — .32y + 61) ° 
— .HSe--'">'y cos (30f + 75) ° (124) 

remembering that C = 8.3 and D = 5.6 (p. 376). 

The value of /.i-^7760, when expressed in c. g. s. units is 

^^•^Sox 24X3600-^°' 

which is about 25,000 times the laboratory value (Wegemann, 1905a, 
p. 139). But this quantity y.- is the same as the Misclningsintensitdt 
(Jacobsen, 1913, p. 71), which is a measure of the rate of transfer of 
salts, heat, or other properties of sea water arising from the mixing 
of water particles in the alternating circulation (p. 368). Suppose the 
diffusion of salts and the molecular conductivity of heat to be negligible 
in comparison to the rate of transfer due to the alternating or 
reciprocal changes in the positions of the water particles : then as 
Jacobsen (1913, p. 71) says, the value of this coefficient, the 3Iischungs- 
iiifciisifaf, determined from au.y of the properties should be the same 
under tlie same conditions. He found values ranging from 1.9 to 3.8 
from observations on currents and the distribution of salinities in the 
sea near Denmark. From observations on tidal currents and salinities 
in a neighboring region he obtained the values ranging from 0.3 to 
11.4. The value 30 obtained from temperatures in the San Diego 
region is of the some order of magnitude, but the intensity of the 
circulation in the two regions would probably be different, hence the 
coefficients would be expected to differ. 

The idea regarding the alternating motion of water in the ocean 
held by Kriimmel and Ruppin (1905. p. 36) may be summarized as 
follows : The coefficient of viscosity determined from laboratory experi- 
ments, in which the motion of the water is slow and takes place along 



OCEAN TEMPEItATrSES 379 

parallel surfaces, varies from .008 to .02 for a wide range of tempera- 
tures and salinities. But the idea of laminar flow no longer holds 
when one considers the motion of whole volumes of water, hundreds 
of meters in thiclaiess, throughout which there is a pressure gradient, 
as is often the case in oceanographie problems. In such cases one 
should not use inncre Reibung (viscosity), but Massenwidersland 
(hydraulic friction). 

The character of the motion is no longer simply laminar (one of 
simple sliding to and fro, parallel to a given plane) but the particles 
of fluid leave their surfaces and move in vortices along stream lines 
transverse to the laminar motion. Thus a much greater resistance is 
developed. For example, the values of the coefficient of viscosity 
obtained by Nansen in his ocean researches are 200 to 40,000 times 
the laboratory value. 

The same general idea has been successfully applied to certain 
meteorological problems i-elative to wind, temperature, and humidity 
by G. I. Taylor (1915). He found that the transfer, in a vertical 
direction, of heat and water vapor in the atmosphere followed the law 
of heat conductivity in solids, and that the effect of friction on the 
motion of the air could be taken into account by substituting in the 
general equations of motion a quantity called "eddy viscosity" for 
the laboratory value of the coefficient of viscosity. 

From the observed relation of air temperature to height off the 
coast of Labrador, lie obtained values of the coefficient ; of " eddy 
conductivity" from .57 X lO'' to 3.4 X 10^, corresponding to wind 
velocities varying from 2 to 3.4 Beaufort. Also from observations on 
the relation of wind velocity and direction to height he obtained values 
of the coefficient of eddy viscosity varying from .77 X 10^ to 6.9 X 10^. 
The values of these coefficients are more than 10,000 times the labora- 
tory values, the ratio being of the same order of magnitude as that 
obtained for sea water. 

In general, comparisons of his theoretical results with observations 
indicated a very satisfactory agreement. An especially good agree- 
ment was found between the predicted and the obsei'ved values of the 
angle between the wind and the horizontal pressure gradient at 
different levels. 



380 



MISCELLANEOUS STUDIES 



JANUAEY 



JULY 




100 
350 



130 200 

400 Meters 



350 Meters 



Figs. 4, 5, 6, 7, 8, and 9. Curves Bhowintr the theoretical relation of ocean 
temperatures to depth in a region approximately eight miles west of the 
Coronado Islands. The crosses ( + ) corresjiond to observed temperatures. 



OCEAX TEMPEBATIEES 



381 



20° 
19 










Al 


KII, 




: 


OCTOBER 


18 - 
















- 


A f 


17 _ 
















- 


\ 


16 - 
















- 


\ 


15 - 
14 _ 
13 _ 
12 _ 

11 _ 


^ 


* 












_ 


\ 


10 _ 




vLi. 


^ 




~T 


' 4 T 


-^— _ 


- 


^^x»^ 


9 






1 


t"^^^^^ * 


8 _ 
















_ 


^-— ^-_ ^ ^^^ 


7 


















"" t ~~ -. 






1 






1 




1 


1 


1 1 1 1 1 1 1 



50 



150 



210 




250 



50 
300 



100 
360 



150 200 

400 Meters 



250 



350 Meters 



IS"-, 


MAY 


_ 


NOVEMBER 


17 - 






_ 


X 


16 - 


^^ 




_ 


\ 


15 - 


+ + 
t 




_ 


x^ 


14 - 








— 


x^^ 


13 - 


J 






_ 


^\^ 


12 - 
11 _ 


* 


V 




- 


\^^ 


10 _ 


Vj 


,__v 


- 


^~^^v.^^^ 


9 - 
8 - 

7 




"^ '^^^ TT-f- 


______^ 


^^^^^--....^^^ 






" 


— - — — _ ^~'~~"~~-^~^^__ 








J 1 1 


1 


1 1 1 1 1 1 1 



5J 



10 J 




25,) 



50 
300 



100 
350 



ISO 200 

400 Meters 



250 



300 



350 Meters 



DECEMBER 




100 
350 



150 200 

400 Meters 



1 r 

300 350 Meters 



Figs. 10, 11, 12, 13, 14, and 15. Curves showing the theoretical relation of 
ocean temperatures to depth in a region approximately eight miles west of the 
Coronado Islands. The crosses ( + ) correspond to observed temperatures. 



382 MISCELLANEOUS STUDIES 



Comparison of theoretical and observed monthly temperatures at 
depths from 40 to 600 meters in the San Diego region. 
The values computed from equation (124) and entered under the 
observed temperatures given in table 6 are seen to agree well with the 
mean of the observed values, thus proving the approximate correctness 
of the form of the function deduced from theory. These computed 
values and those from table 12 for the surface are also shown graph- 
ically by figures 4 to 15. on which are entered a number of points 
corresponding to actual observations (Michael and ilcEweu, 1915, 
1916). 

Solution of the prohlmi of temperature reduction due to upwclling 
with application relative to the 40 meter level in 
the San Diego region. 
In the relation of mean annual temperature to depth 

e,„=Cc>^!>->rD = <i> (125) 

Wi 

deduced from the differential equation (80), A= — ^ equals the 

1^ 

velocity divided by the difFusivity, but C and D are con.stants of 
integration. From observations of the mean annual temperature at 
a series of depths thase constants can be determined as was done on 
pages 372 to 376, and they correspond to the particular physical con- 
ditions under which the observations were made. For the same value 
of D, the deep water temperature, but a different value of one of the 
physical conditions, say the velocity Wj, what will the temperature <^ 
be? To answer this question it is necessary to know the relation of 
each constant to the velocity M',. The relation of X to n\ is known 
and it remains to find the relation of C to u\. 

In the limiting case in which A = 0. denote the new value of the 
constants by C. D' and A'; then expanding the exponential gives 

cf>' = C'e^'^ + D'= C'X'u + C + D' = B'g + /)/ (126) 

where B'^C'X' is the constant temperature gradient corresponding 
to zero vertical velocity. 

^^* C=— A(A) (127) 

A 

^""^ D^D'f.W (128) 

where /,(0) =/„(0) = 1, since, as A = 0. C = (" and D= D'. 



OCEAN TEMPEBATUSES 383 

Substituting in equation (125) gives 

.^ = + ^A(A)e^'' + Z?'A(A) (129) 

where the forms of the functions /i(A) and /^(X) are to be deter- 
mined. At the greatest depth, i/, for which the theory is valid, assume 
the temperature to have the constant value <^i for all values of X. 
What effect will a vertical velocity have on the temperature above this 
level? The right-hand members of the equations (126) and (129) are 
equal for y = y^, since <^i is assumed to be independent of \ at that 
depth, that is, 

4>^=-^ fr{k)c^y^+ D'f,{\) =B'rj, + D' + C (130) 

A 

Therefore from equations (129) and (130) 
<#. = ^A(A)eX"+i)7.(A)— •f^A(A)eX^'— i)73(A) + B'2/i+^'+C" 

A A 

= ^/\(A)[eX''-eX«']+ B'y, + P/. (131) 

A 

Subtracting the general value of <^ given by equation (131) from 
the particular value <^' corresponding to the case of no upwelling 
given by equation (126) gives 

^'_^ = B'(y — 2/J— ^A(A)(f^"— f^^") = A<^ (132) 
A 

the reduction in temperature due to the upwelling velocity rt\ = — ju-A. 

It remains to determine B' and the form of the function f^iX). 

The temperature change due to the variation of velocity with the 

time was found to be approximately 

— Ce'^« (l — e- —■ ^i° "' ) 

(equation 116), where the velocity is 

w = iVi{l -\- r cos at) 

and the value of r in the remaining terms is neglected, for the fol- 
lowing reasons. The values of the constants A^ and B^ depend mainly 
on the seasonal variation in temperature due to radiation ; if there 
were no such variation they would be zero, in which case the variation 
in temperature with respect to time would be due entirely to that of 
the wind. The temperature reduction is therefore approximately 



384 



MISCELLANEOUS STUDIES 



where R is the constant average reduction. A variation of the velocity 
from its minimum to its maximum value, that is, from to 2u\ as at 
varies from to 'Itt produces a variation of temperature reduction from 

lR+e^y{l — e^\ C to R+e^yfl~e-^\ cl 

that is, as the velocity varies from to 2u\ the temperature reduction 
increases bv the amount 



\«A , R' 



-)-?]} 



from which the temperature reduction due to tlie velocity u\ is 

A^=C{c^y)l(e^^-e-^\^Ce^y,mh{^\ (133) 

The approximate temperature reduction deduced by two inde- 
pendent methods is given by equations (132) and (133), respectively. 
Equating these two values and using ecjuation (127) gives 



Ce^" sinh 
B' 



A (A) e'^" sinh (^\ 



A 



= A<^ 



(134) 



Solving for tlie unknown function /](A) gives 



A (A): 



^(.y — yi) 



e\y — gXi/i _|_ g\!/ sinh 



(^-?) 



(135) 



Since A is assumed to be independent of y. the variation of the 
right-hand member of equation (135) with respect to y is a measure 
of the error in the two expressions for A<^. Also a comparison of the 

AC 



theoretical temperature gradient. B'-- 



7.(A) 



(equation 126). which 



would be expected in case of no upwelling with observations of deep 
water temperature in sucli regions affords an additional test of the 
theorj-. The following values of the constants of equations (125) and 



OCEAN TEMPEEATVBES 



385 



(133) computed on pages 376 to 378, C = 8.3, D^5.6, X-- 



-.004, 



iv, = —n, 2A = 600, ^^ = 



KlVi 



.237 and sinh ^^^^^ = .24 are used in 

a 



table 8, which gives the relation of f, (A) (equation 135) to y. 



Table 8 
The variation of f, (X) ivith respect to y. 



y 


Hy-y^) 


fX!/ — fX!/i_|_eX!/sinh( — ] 


/iW 


30 


2.28 


1 009 


2 26 


40 


2 24 


0.965 


2. 32 


50 


2.20 


924 


2.38 


60 


2.16 


0.885 


2.44 


70 


2.12 


0.846 


2.51 


SO 


2.08 


0.809 


2.57 


90 


2.04 


0.744 


2.63 


100 


2 00 


0.740 


2.70 


200 


1 60 


466 


3.59 


300 


1 20 


282 


4.26 


400 


80 


160 


5 00 


500 


0.40 


076 


5.26 


600 


0.00 


0.022 


00 


700 








800 













Table S .shows the variation of A (A) with respect to depth to be 
less than 20 per cent in the depth interval from 30 to 100 meters, 
hence the two methods (equation 134) of estimating A(/) are in good 
agreement within this interval. The value of /i(A), corresponding to 
30 meters, the .smallest value of y for which the theory is valid, gives 
the best estimate of /i(A), and hence of B', since the variation of /i(A) 
with respect to y is least for small values of y. Substituting the 

numerical values gives 

AC 



B'-- 



7i(A 



-=—.0148 



(136) 



the mean annual theoretical temperature gradients that would be 
expected at latitude 32° 30' if there were no up welling and the other 
conditions remained the same as those prevailing when the observations 
in the San Diego region were made. The observed temperature 
gradient at the depth of 600 meters not near shore would be inde- 
pendent of seasonal variations and would be but little affected by 
horizontal currents, and is in the depth interval of the observations 
from which the constants of the theoretical formula for mean annual 
temperatures were computed. 



386 



MISCELLANEOUS STVDIES 



Table 9 
Vertical temperature gradients in degrees per meter at the depth of 600 meters. 



Indian Ocean 


South Atlantic Ocean 


North Atlantic Ocean 


Lat. 30°to35S 


Lat. 30° S 


Lat. 30° N 


-.004 


-.0135 


-.0025 


-.006 


-.0160 


-.0080 


-.007 


-.0160 


-.0090 


-.0085 


-.0165 


- 0110 


-.0095 


-.0210 


- 0150 


-.0115 


-.0260 


-.0155 


-.0130 




-.0160 


-.0140 




-.0175 










North Pacific Ocean 






Lat. 30° to 35° N 




- 0075 


-.0140 


-.0215 


-.008 


-.0150 


- 0215 


-.0095 


-.0150 


-.0220 


-.0095 


-.0150 


-.0235 


-.0100 


-.0155 


-.0245 


- 0100 


-.0155 


- 0250 


-.0105 


-.0160 


-.0260 


-.0120 


-.0170 


-.0290 


-.0120 


-.0195 


-.0305 • 


-.0125 


-.0205 


-.0315 
- . 0350 









Table 9 shows the observed temperature gradient at the depth of 
600 meters and at the approximate latitude 32° 30', corresponding to 
widely different positions between latitudes 30° S to 35° S and 30° N 
to 35° N, and their average is probably a good approximation to the 
normal gradient at 600 meters. The average of the 22 observations 
in the Indian and Atlantic oceans (Schott, 1902, pp. 158-160) is 
— .0126 degrees per meter, and the average of the 31 observations in 
the North Pacific (Makaroff, 1894, pp. 456-464) is —.0179. The 
theoretical result — .0148 agrees well with these observations. 

The reduction of the mean annual temperature at a given level y 
for a given velocity u\ is proportional to CeM' (equation 133), that is, 
the reduction is proportional to the difference between the tempera- 
ture at the depth y and the constant D. Therefore the temperature 
reduction corresponding to a given month is proportional to the differ- 
ence between the temperature at that time and the same constant D. 

That is, 

A<i>i _ 4>t — D 4>t~D 

A^ ~ \Ce^y + D) — D ~ <t>,u—D 



(137) 



OCEAN TEMPEh'.irUEES 



387 



where <t>t is the temperature at the time t, A<j)t is the corresponding 
reduction, <^„, is the mean annual temperature, and A<^ is the reduction 
of the mean annual temperature. Substituting the numerical values 
for ij equals 40 meter.s, from page 385, equation (137) reduces to 

^<^' = iIt^(8.3) (.852) (.24)= (^1^) 1.7 = . 227<^, _ 1.27 

(138) 
Svibstituting the observed values of <^, at the depth y equals 40 from 
table 6 in equation (138) gives the values of A<^( entered in the 
second line of table 10. 

Table 10 
The monthly temperature reduction at the depth of 40 meters near San Diego. 



t 


1 


2 


3 


4 


5 


6 


7 


8 


9 


10 


11 


12 


AOt 


1.75 

-.10 

1 65 


1.75 

-.27 
1.48 


1.68 

-.37 

1.31 


1.23 
-.37 
0.86 


1.11 

-.27 
0.84 


1.18 

-.10 

1.08 


1.41 

-.10 

1.51 


1 61 

.27 
1.88 


2 09 

.37 

2.46 


2.55 

.37 

2.92 


2.23 

.27 

2.50 


1.91 
.10 

2.01 



But the vertical velocit 



y is u\ ( 1 + .2 cos -M, 



and because of its 



,X"'i'' 



variation with respect to time a correction equal to e"'^ C ~^ sin at 
(equation 116) must be added to these values. The correction for 
this ease is 

.386-1" cos (30f + 75)''=.324cos(30i+75)» = A<^r 

(last term of equation 124. p. 378), and the values are entered in the 
third line of table 10. Finally the fov;rth line gives A<^( -j- A<^,. = A(9( 
the total temperature reduction at the depth j/ ^ 40 meters. 



Computing C from equations (136) and (135) and substituting 
the result in equation (133) gives the expression 

(y — 600) (—.0148) sinh (^^^ e^wk 
■'° + '"''' (^4062 j ' "'" 



e 7760 e 7760 



for the mean annual reduction in temperature at the depth ij xlue 
to the mean annual velocity of upwelling u\. The values of this ex- 
pression corresponding to a series of values of u\ (expressed in meters 
per month are presented in table 11 for the depth y = 40 meters. 



388 



MISCELLANEOUS STUDIES 



Table 11 

Theoretical temperature reduction at the depth of 40 meters corresponding to a 

series of values of the vertical velocity «',. 



W^ 





10 


20 


30 


40 


50 


60 


70 


80 


90 


100 


Temperature 
reduction 


0°0 


0°38 


0°95 


1°67 


2°48 


3°34 


4°1S 


5°00 


5°80 


6°48 


7°07 



From plates 24 and 36 (MeEwen, 1916), and from an examination 
of the temperature data (Michael and MeEwen, 1915, 1916) it appears 
that the temperature reduction at the 40 meter level, inshore averages 
from 2° to 3° more than that ten miles offshore. Also surface tem- 
peratures as much as 9° below the normal have at times been found 
close inshore in July or August, when the normal temperature is 
about 23°, while the reduction of the surface temperature ten miles 
offshore does not at any time exceed 3?5 (table 12). If, corresponding 
to a temperature reduction of 1?7 ten miles offshore, the inshore 
reduction is 1?7 plus 2?5 equals 4?2. the corresponding velocity of 
upwelling inshore would, from table 11, be about twice as great as 
that ten miles offshore. 



Deduction op the Change in Surface Temperatures Due to a 

Vertical Flow op Water near the Surpace 

Statement of assumptions and mathematical formulation of the 

2)rohlem. and solution for the case in which the 

flow is constant. 

The temperature reduction at the 40 meter level due to upwelling 

applies also to the surface water, but owing to the upwelling in this 

upper level the surface temperature will be still more reduced. The 

time rate of change of temperature in the case of no resultant flow 

given by the differential equation (10) on page 342 plus the term 

— u^ — will be the modified rate due to the vertical flow »•„ as on 

page 354. Hence the new differential equation corresponding to a 
vertical flow near the surface is 

dd 



^ = Be-'"y[{a, + a.a) cosat + a,.T + l] — kie—e,)—w „ 

OS 



dy 



(139) 



where k = k^e' 



iiV 



OCEAN TEMPEBATVRES 



389 



In ease »'o is constant, assume for the form of the solution 

e = A(y)smaf + /,(y)eosa< + /3(2/)x + /-,(y)+e, (140) 

where 6^ is independent of t and x. Substitute this expression in 
equation (139), thus obtaining the following equations: 



[". 



(sinaOUA(y)— A;,e-''"/i(y)— «• 






= (141) 



(cos 



aO [-aA()/) + Bf-''.''(«,+a,x)-A-,e-".-''/,(y)-«'„^?^] =0 

(142) 
x\^a,Ber^^y-Ke-'>^yf,{y)~ic,'^-xc,,'^l^'^ =0 (143) 



[ 



Be-''^>'~k,e-''^t'f,iy)—w, 



, rf^i 



dij 



" (hi J 



(144) 



in which r is regarded as a constant. 



In ease of no vertical velocity the variation of (6 — 0^) with respect 
to time is small compared to its mean value, which is independent of 
the time (p. 344). Therefore, assuming this to be true for the present 
case, a good approximation would result if the constant part were 
multiplied by the correct factor ],\e~'"y and the variable part by an 
average value k. Making this change in equations (141) to (144) 
we have the much simpler ones 



af.Ay)-kf;(y)-w,^h^=o 



dlJ 



— o.fAll)—J;f.,{il)—u\ 



df,{y) 



dy 



k.e-^^"fAy) + "'o^^^= a^-Be-^'^ 



k,e-^>^yf. 



.'»'+- (^-t)^ 



: Be-^^i' 



(145) 



-Be-^^y{a, + a._x) (146) 



(147) 
(148) 



From equations (145) and (146) 



Va=+(fc,) 
where l\,^^k — »•„&! and tan Co^ 



cos (a< — e,) + /3(y)x + /,(y) + e, (149) 



K 



390 MISCELLANEOUS STUDIES 

From equation (147) 



Ba. 
and from equation (148) 



f.{y)=~ (150) 



dd 
where-T-^equals — b^M^e-"'-^ which gives 

0,=M,e-^^«+e\_ (152) 

where 0\ is a constant of integration. Substituting these values in 
equation (149) gives 

^^g(a,+ a..)e-^.v^^^ („^-e.) + ^-+ ^^ + '^^-^'r" + ^ + 3/..-^ 

Va^+(A%)- ^'' ^'^ 

(153) 
As on page 343 

,,__ B(a, + a,r )_ ^^^^^ 

yja' + iKV- 
and since the change in temperature due to upwelling near the surface 

is due to the gradient — , only terms involving y should be functions 
dy 

of ?('(,. Moreover, as «•(, increases indefinitely the temperature at the 

lower boundary of this upper layer should approach the constant value 

Therefore, as on page 344 

■ ^^"-' .,e-^^. + ^ + e, (155) 



which reduces to equation (22), (p. 344), when M'n = 0, except that 6., 
takes the place of d^ and the average value of k" takes the place of 
[fc,e"''''^"-'"]-. The latter quantities are small compared to a- and 
therefore the difference between their values makes biit little difference 
in the result. This difference or error comes from the approximation 
made in solving the differential equation (139), (p. 388). 6., is found 
by subtracting the temperature reduction due to upwelling at and 
below the surface (3 meter level) from 0^, therefore in case of no 



OCEAN TEUPESATUEES 



391 



upwelling (9, equals ^3. A second approximation to the solution of 

equation (139) can be found bv substituting for — - its value from 

dy 

the first approximation. The solution is then reduced to 

6= _ - _ g + ^ [cos (at — t.,) 1]-| J- 



Ba^xe^^ B_ 



(156) 



where 



tan e, = 






k 



a'+(k,y 

If M'0^0, equation (156) is identical with equation (22). 



Solution for the case in ^vhich the flow is a periodic fimction 

of the time. 

If the vertical velocity equals 

M'o[l + »' COS (at — £1)] 

the time rate of change of temperature can be obtained from the dif- 
ferential equation (139) in which the last term is multiplied by 

[1 -|- r COS {at — fi)]. 



The new differential equation is therefore 

^=Be-'>^y[ia,+aa)cosat+a,x+l]—k{e~d,)—iv„[l+rcos(at—e,)f^ 
at ' oy 

(157) 

Let d' be the solution already found when r = 0, and let 6" be the 
correction due to r, then 6^^d'+d", and the result of substituting 
in equation (157) is 

-^ + ke" + w^— + w^r cos (at — t,)— + ?(•„/• cos (af — fj— = 

(158) 



392 MISCELLANEOUS STUDIES 

Equation (155), using y instead of {y — 3), gives approximately 
d' and 



^y ^a- + ihy 



[cos (a^ — £,)— lle""'^ (159) 



Substituting this value of in equation (158) and letting 

0" ^= ve'^'-v results in the ordinary differential equation 

-77+ At — H'oOif [«■„)• cos (at £j] -_ [cos {at — u) — 1] 

— ru^Jj^v cos, {at — ej (160) 

where v is a function of t only. Let 

A- — tvjj^ = Av, and Ji ., = — ■ 

Va^+Av 

then equation (160) can be put in the form 

^ + A-,t^ = — rJ7„ jcos (af — ej— ^[eos (2a/ — £3) + cos ej ■ 

+ rWgb^v cos {at ej (161) 

where e^ + tj ^ £3 and £, — t^ = t^. 

When the vertical velocity is directed upward (/■„ is negative, 
therefore 

A-,= (A- — H'„^'i)> I n^i I 

and the last term of equation (161) can be neglected in the first 
approximation, which is 

v = e-'"-*^—rM, I f^='feos {at — e,)— -cos (2a; — £,) — ^cos £X/i + C - 
— ( Fa COS £, + l\ sin £, ~1 ■ , FA", cos £, — a sin £,~| 

= -'--^^^ { L ^F+k? J "° "' + [ ' a- + A/ J-^^^ "' 

r2a cos£,+ fc, sin£,~| . „ J 

rA\cos£s — 2asin£,,~] cos £4 ) ,.,„, 

- 1 2{ia^-+kj) r' ^"'-^kT \ (1^2) 

The arbitrary constant C is 0, since from physical considerations 
the solution must be a periodic function of the time. Substituting 



OCEAN TEMPESATVttES 



393 



{ij — 3) for y in the exponential vc''''" and adding the result to from 
equation (156) gives the following approximate value of the tem- 
perature in case the velocity of upwelling is w„[l -\- r cos {at — tj] 



( i?(a, + a,,.r)f-'"'"-^' 



[■ 



e= - ' ' -_ = cos (a< — £.,)—! 



M 



= +A:= 



+^„ + , 



rir„Bbi{aj-]-a^.r) \ Fa cos e, + /«■„ sin e, ~| . 



Va= + (E) 



Fa COS £, + /«■„ sin £, ~I • 



, r2acos£, + A", sin e,~| . ^ , , r^'-eose„ — 2asin6,~] 



l\ cos €, — a sin £i 



COS at 



Ba.,.rc-^'" , B 



where 



i (.g-6i(!/-3) 



(163) 



tan ( 



a=+(A-,)^ 



(164) 



Theoretical Reduction op the Surface Temperature for Each 
iMoNTH IN the San Diego Region, Due to Upwelling ; 
AND Comparison with Observations 

The theoretical relation of ocean temperatures to time and depth 
developed in pages 368-381 was found to agree well with observations 
from 40 to 700 meters in the San Diego region. The theory developed 
in pages 388-393 is valid for only the upper ten meters ; but no satis- 
factory theory for the intermediate interval from 40 to 10 meters or 
to the surface has been worked out. Now since the temperature reduc- 
tion at the surface depends upon the upwelling in all three intervals, 
it is neeessarj^ to estimate the reduction in this intermediate interval 
for which we have no theory. A method of making this estimate is 
included in the following plan of computing the theoretical tempera- 
ture reduction at the surface. 



394 MISCELLANEOUS STUDIES 

An explanation of s.ymbols used in making the computations will 
be given for reference : 

6' equals the normal surface temperature. 

6 equals the theoretical surface temperature when the effect of 
upwelling is considered. 

6' equals the mean annual normal temperature at the surface. 

Ob equals the constant temperature at the depth 600. 

A6' equals the total theoretical reduction of the surface temperature. 

Ad's equals the theoretical reduction of the temperature at the 
depth of .3 meters which corresponds to surface conditions 
(p. 343). 

A^' equals the theoretical reduction of the surface temperature due 
to upwelling in the interval from 3 to 600 meter.s.. 

A^' equals the mean annual temperature reduction at the 3 meter 
level due to upwelling in the interval from 3 to 600 meters. 

A4>s equals the mean annual temperature reduction due to up- 
welling at the 3 meter level. 

A^' equals the total theoretical reduction of the mean annual tem- 
peratvire at the depth of 3 meters. 

Ai/'', equals the mean annual temperature reduction due to upwell- 
ing in the interval from 40 to 3 meters. 

A^'ta equals the mean annual tempf^rature reduction due to up- 
welling in the interval from 600 to 40 meters. 

Throughout the interval fi'om 100 to 40 meters the temperature 
reduction increases at a constant rate by the amount .36 (table S). 
the velocity is practically constant {^ii\), and the mean annual 

2 3 

temperature gradient is ^. Tii tlic interval from 40 to 3 meters the 

Ij Q 13 1 3 9 

mean annual gradient is — =-^ (table 6), but the mean 

velocity is approximately - (1 -\- q)y, where qu\ is the velocity at 

the depth 3 meters. Assuming provisionally that q^O.l (p. 403) the 
mean velocity in this interval is .55?r,. The temperature reduction 
in any depth interval is proportional to the length of the interval, as 
was shown to be the case in the interval from 100 to 40 meters, and 



OCEAN TEMPEEATUEES 395 

is proportional to the temperature gradient (p. 386). Therefore if the 
velocity were the same in the interval from 40 to 3 meters, as at the 
levels below 40 meters, the following relation would hold 






A4,\ _ V37 /'^' _3.9 
.36-/2.3\go 2.3 



or Af. = (.3G)(^||)=.61. 



But using the provisional estimate 0.55m'i of the mean velocity in this 
interval we have Aij/\ = .55 X -61 = .34. Using the principle (p. 386) 
that for a given velocity the temperature reductions are proportional 
to the temperature gradients 

Act>' = J^'~^^'\ (A^')^ ^'~'^'^'~^"T^^'V a^') (165) 

e'—0b—Ae' d'—6i—Ae' 

Solving for A(f>' gives 

/|^_^^^__Ae\\ -^ (166) 

\6'—e,—Ae's ) 

From page 387. and the value of Ai//'^ we have A(/)'=1.7 + .34^2.04. 
From page 347, the normal temperature is 

e'=— 3.79 cos (30f — 69) ° + 19.5 (167) 

therefore 

A,' = (-3.79 COS (30^ -69)° + 13.2 -A^.^^ ^ ^^ 

since ^,,„„=6?3 (p. 376). 



(168) 



The observed mean annual .surface temperature is 17?0 (p. 375) but 
the normal value le.ss Ac^' equals (19?5 — 2?04) equals 17?46, which 
is ?46 higher than the observed value. This indicates that there is a 
still further temperature reduction of the surface temperature due 
to upwelling at the 3 meter level. From page 390, Oo^^i — ^4>' • 
therefore, if A<^' is added to both members of equation (163) we can 
replace 6. by 6^, and the value of ^ + A<^' differs from the normal 
surface temperature solely because of the iTpwelling at the 3 meter 
level. Therefore 6' — (0 -\- A<f>') equals the temperature reduction 
Ai9'., due to upwelling at this depth. Since only the surface tempera- 



396 



MISCELLANEOUS STUDIES 



tures are required A" can be put equal to k. then l\ will equal k„. 
Prom the value of 6' (equation 24) and equation (163) we have for 
the value of A6's = 6' — (S + A<#>') 



A6'',, = Be-^'"(ai + a,x) 
1 i 



cos (ai — e) eos(a< — e^) 



+ 



Va- + Av 



•WiyBb, ( a + a„x ) ( cos e^ fa cos ei + A-j sin ei~| 

- ^ L a=+A,= J 



x=+A,= 



2A., 



sin 



r ^'^ COS €, — asine,~| , , rSa COS e, + A"o sin €,"] 

^"' "' -[ ' a- + Av r + L 2(4:- + A-.-) J 

[ A, cose, — 2a -sin t, "I 

^^"^^ + [ 2(4a= + V) J 



COS (2aO -c'-'" 



(169) 



Leaving iCg and therefore A, and u uudeterniiued for the present, 
equation (169) can be reduced to the form 

..ff =9 19 i J 1 [ I (■00775HV) eose, 

^" ■' ^- ^ ] .560 V"^274T/^ i ^:;(-2^4 + ^^^'^ 

f cos(30< — €.) cos (30^ — 69) jl .OlSSwy 

"^"" 1V.274 + V -560 r(-274 + Av) 

sin at -\- 



.506 + .259A, 
.274 + A-,= 



.966A..— .1361 
.2/4 + A,- 



+ h' J 



ri.046 CO.S £., -\- A, sin ( 
L 2(1.096 + A,=) 



+ 

COS 2a/ '- 



sin 2a/ + 



:., COS e^ — 1.046 sin £3"] 
2(1.096 + A:/) J 



;i70) 



using the following values of the remaining constants: fti = — .318, 
a„ = — .0166, 5e-=".= 5.9. e, = ]95, e=69, £3=(e, +£,), 6,== (£,, — cj, 
r=.2, a = .523. ft, = .0365. (pp. 347, 351, 376), A = .2, A, = 

.2 — .0365(c„, tan £, =— (p. 394). Assume w^ equals — 3, then 

A^',= .448 — 3.78 cos (30/ — 60) + 3.48 cos (30/ — 69) 

— .113 1 1.58 sin 30/ + .441 cos 30/ 1 =.448 —.69 cos 30/ — .18 sin 30/ 

(171) 

The values of the temperatures and their reductions are given in 
table 12. 



OCEAN TEMPKEATUBES 



397 



Table 12 
Normal surface temperatures and temperature reductions in the San Viego region. 



t= 


1 


2 


3 


4 


5 


6 


7 


8 


9 


10 


11 


12 


means 


6' 


16.55 


15.75 


15.95 


17.11 


18.91 


20.86 


22.45 


23.25 


23.05 


21.89 


20.09 


18.14 


19.50 


^0/ 


-.24 


-.06 


+ .27 


+ .64 


+ .96 


+ 1.14 


+ 1.14 


+ .96 


+ .63 


+ .26 


-.06 


-.24 


+ .45 


A<^' 


1 66 


1.52 


1.50 


1.63 


1.86 


2,15 


2.40 


2.56 


2.58 


2.45 


2.22 


1.93 


2.02 


*^<t>r 


-.10 


-.27 


-.37 


-.37 


-.27 


-.10 


+ .10 


+ .27 


+ .37 


+ .37 


+ .27 


+ .10 


.00 


AB' 


1 32 


1.19 


1.40 


1.90 


2.55 


3.19 


3.64 


3.79 


3.58 


3.08 


2.43 


1.79 


2.47 


A6' obs. 


1.55 


1 35 


1.35 


1.91 


2.81 


3.06 


2.75 


2.65 


2.85 


3.09 


3.29 


2.64 


2.50 


6 comp: 


15.23 


14.56 


14.55 


15.21 


16.36 


17.67 


18.81 


19.46 


19.47 


18.81 


17.66 


16 35 


17.03 


6 obs. 


15 00 


14.30 


14.60 


15.20 


16.10 


17.80 


19.70 


20.60 


20.20 


18.80 


16.80 


15.50 


17.00 


Difference 


+ 23 


+ .26 


-.05 


+ .01 


+ .26 


-.13 


-.89 


-1.14 


-.73 


+ .01 


+ .86 


+ .85 


+ .03 



•From line 3, table 10 (p. 387). 

The agreement between the predicted monthly temperatures and 
the observed averages is very satisfactory. Moreover, from the rela- 
tion of the vertical velocity to depth deduced from hydrodynamieal 
principles, and shown by table 13, the velocity u\ at the 3 meter level, 
would be .116h\, where it'i is the velocity below the 40 meter level. 
That is, the value of w^ to be expected from that deduced from deep 
water temperautres (p. 403) is .116 X ( — 31) equals — 3.6, which 
agrees well with the value — 3.0 deduced from the surface temperature. 



Deductions Relative to Oceanic Circulation in the San Diego 
Region Based on Ekman's Hydrodynamical Theory 

Zfippritz (1878) obtained some theoretical results relative to oceanic 
circulation, from the general equations of motion of a viscous fluid, 
and some of his conclusions have been widely used by oeeanographer.s 
and geographers; but a critical examination made in the light of later 
observations showed that his conclusions do not apply to conditions 
found in nature. These erroneous conclusions are due to hi.s failure 
to take into account the deflecting force of the earth's rotation and 
to his use of the laboratory value of the coefficient of viscosity. The 
importance of the effect of the earth's rotation on currents in the air 
and ocean was pointed out long ago by Hadley, Coriolis, and Ferrel ; 
but with the exception of free currents, that is. currents moving by 
their own inertia, the deflecting force due to the earth's rotation wa.s 
thought to be so .small that it could be neglected until Bjerknes 
(1901) first made clear the importance of this deflecting force iii the 
ca.se of forced currents. 



398 MISCELLANEOUS STUDIES 

Ekman (1905) also used the general equations of the motion of a 
viscous fluid, but included the deflecting force due to the earth's 
rotation, and used in place of the coefScient of viscosity a constant 
whose value was estimated by applying his formal solution of the 
equations to field data. That is, he used a virtual value of the co- 
efficient of viscosity in order to take into account the effect of the 
irregular vortex motion which greatly increases the magnitude of the. 
mutual reaction between the adjacent water layers. 

On the simple assumption that the depth of the region considered 
is large and the coast is at a sufficiently great distance Ekman (1905, 
p. 7) deduced the effect of a wind, constant in magnitude and direc- 
tion, over the whole region. His results for the northern hemisphere 
are. for the velocity of the water, perpendicular and parallel respec- 
tively to that of the wind, 

U' = Foe-"!' cos (~ a!j\ (172) 

r'=V,e-"«sm(j^ — aij\ (173) 

Where V„ is the absolute velocity of the water at the surface y is the 
depth below the surface and o is a constant. The value of a (Ekman, 



1905 



, p. (5) is n = J 'I'" ^'^" '^ where o) is the angular velocity 

of the earth. <f> is the latitude, /x- is the virtual coefficient of viscosity, 
and g is the density of the water. From equations (172) and (173) 
it follows that the surface water velocity (where y equals zero) makes 
an angle of 45 degrees to the right of the wind velocity, and the angle 
increases as y increases. "When y has such a value (denoted by D) 
that the water velocity has the opposite direction to that of the sur- 
face, that is, when 

ay = aD = 7r=DJ1^iI}R± (174) 



, ^ J qio sin <i> 



the magnitude of the velocity is r"^ or .043 times its surface value. 
D is called the "depth of frictional influence," since the water velocity 
below that depth produced by a wind over the open ocean is but a 
small fractoin of that at the surface. From an estimate of the relation 
between the wind velocity and its tangential pressure and the eorre- 



OCEAN TEMPEEATDEES 



399 



spending ocean eiirreut produced, Ekman (1905, p. 42) concluded that 



the surface velocity Vg would be approximately 
D would have the approximate value 

7.6 



■0127 
Vsin 4> 



D 



V sin</> 



meters 



/( and that 



(175) 



where /; is the wind velocity in meters per second. Thus for a wind 
velocity of ten miles per hour (5.1 meters per second) and at the 




Fig. 16. Components of the water velocity U' and V perpendicular and 
parallel res]ieetively to the wind, and the velocity of Vc in a direction perpen- 
dicular to the coast. 

7 6X51 
latitude 35° D would equal " =^ 51 meters, and for a velocity 

V sin (t> 
of fifteen miles per hour D would equal 75 meters. Solving equation 

(174) for fi.- gives 

„ D- . .0000729, . ,„. 
fi'^^qw sin <f> = 7, (sni <^)D- 

which equals 217 in c. g. s. imits, when T) equals 7500 cm. and 
<^ equals 35°. 

The relation of vertical velocity to depth will now be deduced from 
the results of Ekman 's theory. 

Let V make an angle A with the coast (fig. 16) and V the angle 
(90-)- A) ° with tlie coast, then the velocity perpendicular to the 
coast is, from equations (172) and (173), 

y sin A -K C/' sin (90 -(- A) = Fc 



400 MISCELLANEOUS STUDIES 

where a velocity directed away from the coast is regarded as positive. 
That is. 



Vc = "Foe""" - cos A cos 



n — 0// j+ sin A sill H— "A c 
= V^e-'y cos (j — ay —A J ( 176 ) 

Let z equal the distance perpendicular to the coast, then Vc from 
equation (176) is the limiting value of the velocity perpendicular to 
the coast as z increases. Also, adjacent to the coast where z equals 
zero, the velocity perpendicular to the coast must be zero. Let the 
velocity perpendicular to the coast at the distance z be given by 
the equation 

V=Vcf(z) (177) 

where /(0)=0 and f{z) =1 as z increases. The removal of 
water at and near the surface due to a flow away from the coast 
decreases the pressure at the lower levels, and gives rise to a com- 
pensating flow of deep water toward the coast. Therefore in a coastal 
region where the surface water flows away from the coast there is a 
compensating upward flow of deep water. 

Denoting the vertical velocity by W, the equation of continuity is 

dV dW 

^+^=0 (178) 

dz dy 

neglecting the variation of the component parallel to the coast. Tliere- 
fore from equation (177), assuming 

W^f,(z)f,{y) (179) 

we have 



dfM 



+ /.<.-)%^ 



f]80) 



dz dy 

To .solve equation (180) let 

^^ = Mf,iz) (181) 

where M is a constant. Then from equation (176) and (180) 

'^^'''■'l=—MVr^—MV, €-<"> cos ( T — ay — A ] (182) 



dy 



(^l-ay-x) 



OCEAN TEMPEEATVUES 401 

fi-om \vliic-h we have 

fAu) = —^1^0 i e-"" cos r^^—ay — xyhj + C, 

= -j sin A sin ay — cos A cos ay r e-"" -\- C^ 

MV \/2 

— ° ^ -e-oi/cos (ay + A) +C, (183) 



2« 
where C, is the constant of integration which must have the value 

MV \/Y 
^ COS A in order that /^(O) may equal zero. From equa- 
tions (176, 177, 179, and 181 ) it follows that the horizontal and vertical 
components of the velocity are respectively 



V = f(z)V„e-'"-' cofi 



W = — A(3)* ^°^ 



(I-«.'v-a) 

= + / 6-"^ cos ( - — ay — X](hi { MVo 
'a J \4 J ) 



(184) 



4r{f""(4'-«"-0 



, cos A ,, 

dy j^l^o 

V2a ) 



= ^L-".vcos(ai/ + A)— cosA !-.^(^ (185) 

V2ffl ] \ f?2 

Since the horizontal velocity of the siirfaee water is proportional to the 
wind velocity (pp. 363, 398) it follows from equation (185) that the 
vertical velocity of the water is also proportional to the wind velocity. 

The differential equation of a stream line is in general -^^ equals 
the slope of the curve ecjuals — equals 



r (it \ , cos A )rf/(2 

— -, / (■-•'y cos I a\\ — A \hj ^=\ -^r- 

dy _}J \4 / • \/2a \ dz 



dz 



e-'"'jcos/'- — ay — aM/(2) (186) 

which can be reduced to the exact differential equation 



df{z) 



e-"" cos ( - — ay — A | rZy 



/(2) " 
whose solution is 



\ ( e-'v cos (- —ay ~ \\dy — ^^=1 (187) 
[cos A — c-"" cos (ay + X)]f{z) = C„ (188) 



402 MISCELLANEOUS STUDIES 

where C„ is a constant of integration corresponding to a given stream 
line. From equation (185) the upward flux through a horizontal area 
of unit width and length z measured perpendicularly to the coast is 



S-'— 



[cos A — e-"!' cos (az + X)]f{z) 



aV2 
Eembering that /(0)^0 and /(^) = 1 as z = oa 



(189) 



{\y,,^_y^^[<^o^^-'^-''^o^«'y + ^)]f(^) (190) 

Jo «V2 

and that the maxinuun numerical value for a given value of y is 

C';ra,=.-YA^^l^^ri^9ll!^I>+m (191) 

Jo «V2 

which approaches tlie value — ("^S^) as V increases, the ratio R 

of the upward flux tlirough a horizontal area at the depth y of unit 
width and length z measured perpendicularly to the coast to the total 
upward flux is 

j^_ J„ "^^ ^ [cosA — f-'"'cos (gjy + A)1/(2) ,-^^2) 

V„ cos A cos A 

Therefore the parameter C„ in the equation of the stream line (equa- 
tion 188) ecjuals the ratio R multiplied by cos A, and the flux between 
any two adjacent stream lines of a series in which tlie increments of 
C, are equal is constant. 

The mean wind velocity of the 5 degrees square of the U. S. Coast 
Pilot Charts (Moore, 1908-11) west of San Diego was found to be 
about fifteen miles per hour in a southeasterly direction, approxi- 
mately parallel to the coast. Therefore for the San Diego region the 
angle A in equation (185) is zero, and the vertical velocity at the 
depth )/ is, from equation (185), proportional to [1 — c""^ cos ay] 

where a =^ -= — (p. 398). The values of this function are tabu- 

lated with respect to depth in table 13. 



OCEAN TEMPEEATVBES 



403 



Table 13 



Tabulation of the function I J g- 75 cos 



7r!l \ 

75 / 



y 


UL TTlJ 

l-e-75 cos=^ 


y 


IIL irv 
1-e-io cos=^ 








18 


.658 


1 


.043 


19 


.685 


2 


.085 


20 


.710 


3 


.116 


21 


.737 


4 


.166 


22 


.760 


5 


.207 


23 


.783 


6 


.246 


24 


.805 


7 


.288 


25 


.825 


8 


.325 


30 


.913 


9 


.361 


35 


.977 


10 


.399 


40 


1 02 


11 


.436 


50 


1.067 


12 


.471 


60 


1.065 


13 


.515 


70 


1.052 


14 


.535 


80 


1.034 


15 


.568 


90 


1.019 


16 


.600 


100 


1.007 


17 


.630 


infinity 


1.000 



The relation of the velocity to depth was deduced from hydro- 
dynamical eonsidei-ations, but its relation to distance from the coast, 
which requires the determination of the function fiz) (equation 177. 
p. 400), did not result from the foregoing reasoning, but will now be 
considered. Prom equation (177), page 400 /(0)=0 and f{z)= 1 
as z increases, and for large values of y off San Diego, equation (185) 
becomes 

y„ df(z) 



W=W^- 



«\/^ 



dz 



(193) 



where (pp. 377, 388) TFi = — 31 meters per month where z equals 10 
miles, and equals double that value or 62 meters per month, where 
z equals zero. From page 363, for an average wind velocity of 15 miles 
per hour or 7.5 meters per second 

^^ .0126X7.5 TO' . A 

Kn = =: .12d meters per second 

Vsin 35° 



404 MISCELLANEOUS STUDIES 



equals 324.000 meters per month and a equals ;^^ (p. 402). Substi- 

tuting these numerical values in equation (193) and expressing z in 
miles gives 



dz 

and 

dfiz) 



^^(^)— 0210 for z = 0, 



= .0105 for 2 = 10. (194) 



dz 

While these conditions, which f(z) and must satisfy, do not 

determine the functions precisely, they suffice for a rough estimate. 
The following form 

/(2) = l_A-,e-"i^— (1 — /.-Je-''^' (195) 

has the value zero when z equals zero and approaches 1 as 2 increases 
indefinitely for all positive values are of h^ and lu, and difEerentiating 
with respect to z 

.^^ = hXe-'"' + h„{l — k, ) e-''^-' (196) 

dz 

The above expression for — ^— satisfies the conditions expressed by 

equation (194) for the following values of the eon.stants found by trial : 

/,^ = 01, /,i = .93, /u=.17, (1 — A-i)=.07. 
Therefore from equation (193) the vertical velocity at any depth ?/ 
equals 

W = — 2960 ^^4^ = — 29G0 f.0093r-'"'— .0119e-''--) (197) 
dz 

and from equation fl92) the ratio of the upward ilux within a dis- 
tance z from the coast to the total flux is proportional to 

f(z)=l — .9.3e-»'- — .07f-'-' (198) 

where z is the distance from the coast in miles. The values of f{z) 

df(^) 
and -~ — are tabulated with respect to z in table 14. 

az 



OCEAN TEMPEBA'TDEES 



40o 



Table 14 
Tabulation of the functions f{z) and 



df{^) 
dz 



z 


f{z) 


dm 

dz 


z 


/(2) 


dm 

dz 








.0212 


40 


.380 


.0062 


1 


.020 


.0192 


50 


.430 


.0057 


2 


.040 


.0175 


70 


.530 


.0046 


3 


.060 


.0161 


100 


.660 


.0035 


4 


.075 


.0150 


200 


.870 


.0013 • 


5 


.090 


.0139 


300 


.950 


.00046 


10 


.150 


.0105 


400 


.980 


.00020 


15 


.190 


.0089 


500 


.994 


.00006 


20 


.240 


.0080 


700 


.9992 


.00000 


30 


.310 


.0070 


1000 


.99995 


.00000 



Tluis it appears that 90 per cent of the upward flux is confined to 
a coastal belt about 250 miles wide. Finally the stream line equation 
(188) becomes 



e- tFcos i!L 
(5 



[1 — .93e- 



.07* 



C„ 



(199) 



for the San Diego region, and the stream lines corresponding to C, 
equal 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 are shown in 
figure 17. 

Meters Water surface Cs 






150 
Miles 
Fig. 17. Traces of theoretical surfaces of flow on a vertical plane perpen- 
dicular to the coast. The flow included between any two consecutive surfaces 
is one-tenth of the total amount. 



406 MISCELLANEOUS STUDIES 

Figure 17 represents the component of the hypothetical circulation 
in a plane perpendicular to the coast corresponding to a uniform wind 
.over the whole region, in which the bottom bends sharply upward at 
the coast, but gives some idea of the actual circulation. In examining 
the figure it must be noted that the vertical is very much greater than 
the horizontal scale. In fact, if the horizontal scale were the same 
as the vertical one actually used the diagram would be about one and 
one-half miles in length. 



Deduction of the Upwelling Velocity off San Diego from the 
Observed Relation of Salinity to Depth 

If the rates of molecular diffusion of salts and conduction of heat 
are relatively very small as compared with the rate of transfer due to 
the alternating circulation (p. 368), the differential equation 

^ = ^=^_W^ (200) 

(equation 80, p. 368) applies in general where the constant fj.- is a 
measure of tlie rate of transfer, and the dependent variable is the salt 
concentration or temperature. An application to temperature data 
has already been made, and we have only to replace 6 by the salinity 
<Sf in the temperature ecpiation and its solution already worked out 
(pp. 375-378) in order to obtain the corresponding formulae for 
salinity. However, the salinity data are too incomplete to furnish 
reliable estimates of averages for each month, and it seemed best to 
use the data taken in the same region ^Section 40 J for each of the 
three months, Augu.st, 1912, February, 1913. and April. 1913, which 
correspond to an interval of less than one year. These data are 
presented in table 15. 



OCEAN TEMPEllAl'UriES 



4U7 



Table 15 
OVuerved Salinities for Aucjust, 13U, February, WIS, and Aprii, WIS, 

in Section 40^ 



Depth 


Salinities 


y 


((=2) 


(( = 4) 


((=8) 


Mean annual 


February 


April 


August 


values 





33.47 


33.58 


33.75 


33.61 


10 


33.47 


33.58 


33.69 


33.58 


20 


33.44 


33 58 


33.58 


33.51 


30 


33 42 


33.61 


33.54 


33.48 


40 


33.46 


33.66 


33.57 


33.52 


50 


33.50 


33 73 


33.65 


33.57 


60 


33.54 


33.79 


33.73 


33.63 


70 


33.57 


33.85 


33.57 


33.67 


SO 


33.62 


33.90 


33.81 


33.72 


90 


33.66 


33.94 


33.85 


33.76 


100 


33.70 


33.99 


33.88 


33.79 


150 


34.03 


34.19 


34.07 


34.05 


200 


34.25 


34,30 


34.17 


34.21 


300 


34.32 


34.33 


34.23 


34 27 


400 


34.33 


34.34 


34.28 


34.30 


500 


34 36 


34.35 


34.32 


34 34 


600 








34.40 


800 








34.48 


1100 








34.53 



From the formula for salinity (replacing 6 by S in equation 117) 
it follows that the mean of any two salinities corresponding to a tinT? 
interval of six months would equal approximately the mean annual 
salinity. Accordingly, the means of the salinities for February and 
August are assumed to be the mean annual salinities in this case. The 
constants C, D, and A of equation (117) were found as in the case 
of temperature data by fitting the equation 

S,„ = Ce->^v+D (201) 

to the observed mean annual salinities. .Si,,,. Then the observed mean 
annual salinity was subtracted from each of the entries under February 
and April, and the expression 



C{^^\e 



e'^i' cos (30^ + 75)° 



was subtracted from each of these, using the same numerical values 
for M'l, r and a as on page 377, and the value of (J determined above. 
The remaining expression 

il/e"'" cos {at -\-h^y — e') 



408 



MISCELLANEOUS STUDIES 



(p. 377) was fitted to these remainders. The values of the constants 
thus found are D == 34.55, C = — 1.25, A = —.005, M = —.6, 
.€' = —65. Hi = —.0075, ^1== 10,600, n',=—53, &i = — .00495. The 
value of &i determined from equation (121) exceeds numerically the 
value — .00175 determined from the observations. Expressing the 
angle in degrees, these values are — .28 and — .10 respectively. The 
values fi- = 10,600 and \\\ =^ — 53 obtained from the salinity data are 
in good agreement with the values 7760 and — 31 obtained from the 
more complete and extensive temperature data (p. 378). The com- 
puted and observed values of the remainders and of the mean annual 
salinities are entered in table 16 as an additional test of the theory. 
The computed remainders were obtained from 

__6e-oo75y(,os (30« — .ly-f 65)° 

and the computed mean annual salinities were obtained from 

34.55 — 1.25 e-""-'". 



Table 16 

Computed and Observed Remainders for February and April, and the Computed 

and Observed Mean Annual Salinites 



Depth 


Remainders 


Mean 


annual 


t = 2 


Feb'. 


« = 4 


April 


Salinities 


y 


Computed 


Observed 


Computed 


Observed 


Computed 


Observed 


50 


.14 


-07 


.32 


.16 


33.53 


33.57 


100 


.07 


-.09 


.21 


.20 


33.74 


33.79 


150 


.02 


- 02 


.13 


.14 


33.96 


34.05 


200 


.00 


.04 


.08 


.09 


34.04 


34.21 


300 


-.01 


.05 


.03 


.06 


34.22 


34.27 


400 


-.01 


.03 


.01 


.04 


34.33 


34.30 


500 


-.01 


.02 


.00 


.01 


34.40 


34.34 


GOO 










34.44 


34.40 


800 










34.48 


.34.48 


1100 










34.50 


34.53 



The mean velocity of upwelling can also be estimated from the 
salinity distribution in the upper 30 meter layer, and by an entirely 
different method. A comparison of this value with the two estimates 
made with the aid of theoretical results ah-eady presented affords a 
severe test of the theories and gives an idea of the reliability of the 



OCEAN TEMPEBATVBES 



409 




Water Surface 



Coast 



results. lu dealing with mean annual values we can assume all con- 
ditions to be independent of the time, from which it follows that the 
total amount of water in a given volume remains constant and the 
total amount of salts remain constant. Tlierefore the rate of flow of 

water and salts into the volume must 
equal the rate of flow out of the 
volume. 

This principle will be applied to 
two difEerent volumes, thus giving two 
estimates of the velocity of the up- 
welling. First, consider a vertical 
column (fig. 18) whose cross section 
is a square of unit area and who.se 
base is at the depth y., where the 
salinity has its minimum value (Mc- 
Ewen, 1916, p. 272). 

The explanation of symbols used 

follows : 

8 = the salinity at any depth y. 

Sg = the salinity at the surface. 

S^ = the salinity at the depth .y„. 

To 1^1 = the vertical velocity at the 
depth y,, W^ is the maximum 
value, and corresponds to large 
values of y (table 13). 

y = the horizontal velocity. 

E =^ the rate of evaporation at the 
surface. 




bottom 



Fig. 18. Eectangular volume of A flow into the volume is regarded 

■(vater from the depth y, of mini- 
mum salinity to the surface, used as negative, and a flow out IS regarded 

in determining the velocity of up- positive, the vertical distances and 

welling from salinity. *^ ' 

velocities are regarded as positive 

when directed downward from the .siirface, and horizontal distances 

and velocities are positive when directed away from the coast. 

Because of the invariability of the amount of water in the volume 



r„^Y, — E +(vdA = 



(202) 



410 MISCELLANEOUS STUDIES 

where dA is an element of the vertical surface enclosing the column, 
and the integral is taken over the whole vertical surface. Similarly 
because of the invariability of the amovint of salts in the volume 

r„W,S„ +j'vSdA = 0. (203) 

Let 

S = 8 + AS (204) 

where <S' is the constant mean salinity for the whole volume and AS 
is a variable increment. Then equation (203) becomes 

r„W,S., + S CvdA + Cv(AS)dA = ' (205) 

and substituting the value of | Yd A from equation (202) we have 

r„W,S._ — 'S{rJY, — E) + fv(AS)dA = (206) 

or solving for W^ 

— SE— CviAS)dA 

W,^ ^ (207) 

i\{S. — S) 

An estimate of | V(AS)dA can be made as follows: Let the 

vohnne be so turned that two of its parallel faces are parallel to the 
coast line and therefore perpendicular to the horizontal velocity V 
directed away from the coast and given by equation (p. 401) 

r = f{z) r^e-oy cos C^ - an ^ (208) 

Then neglecting the variation of the salinity in a direction parallel to 
the coa.st, the integral 



ry(A^')(L4=.- fv,{AS),du+ Cv,{AS),dy 



(209) 



where Y^ and (AS), correspond to the face next to the coast and "F, 
and (AS), to the face farthest from the coast. From a study of our 
salinity observations (ilcEwen. 1916, especially plates 20, 21, 22, and 
24) made from five to fifteen miles offshore, it appears that the hori- 
zontal gradient parallel to the coast is negligible as compared to that 
perpendicular to the coast, thus justifying equation (209). The 
numerical values of the horizontal salinity gradient per meter esti- 
mated from our observations are given for a series of depths in table 17. 



OCEAN TEMPERATDEliS 



411 



Table 17 
Mean horizontal aalinity gradient per meter during the Kummer for a seriet 

of depths 



Depth, y 





5 


10 


1.5 


20 


25 


30 


Salinity 
gradient, A(S' 


6X10-' 


6X10-" 


3X10-" 





-10-" 


-3X10-" 


-6X10-" 



Our salinity data indicate that (AS') is practically zero in winter, 
hence the mean annual value would be about half of that entered in 
the table. 

Owing to the .small value of (T^j — V.,) compared to the mean 
value V and because AS'^(AS)o — (A.S')j equation (209) can be 
written in the form 



j'v(\S)dA^j'v(AS')d,j 
From equations (207, 208, and 210) we have iinally 

I {AS') c-"" cos (|— «yj '^U 



(210) 



-SE — VJ{z) 



W,^ 



(211) 



■i\iS,— S) 

In order to check the above results the same principle will be 
applied to a different volume (fig. 19). The stream lines (fig. 17) 
being traces of surfaces of flow on a plane perpendicular to the coast, 
two such planes, two surfaces of flow, and two horizontal planes 
inclose a volume such that the component of the velocity along a line 
parallel to the coast is the same for each vertical plane. Hence the 
vertical flux through a horizontal section of this volume must be 
independent of the depth of the section, in order that the total quantity 
of water inclosed by these surfaces may be constant. Consider the 
volume inclosed by two surfaces of flow, two vertical faces perpen- 
dicular to the coast and parallel to the plane of the paper at unit 
distance apart (fig. 19), and two horizontal sections at the depths y^ 
and !/, of which the upper form.s the base of a rectangular prism 
extending upward to the surface of the water. 

Let t\W^ be the mean vertical velocity at the depth y,, and )\Wi 
that at the depth y„, then i\W^B^ must equal r„W,B„ where 7?. ^'iid 
fi, are the areas of the upper and lower sections respectively, whence 
the section areas B, and B„ must satisfy the equation 

B„ r, 



(214) 



412 



MISCELLANEOUS S2UVIES 



For the whole volume inclosed, from the base B., to the water 
surface, the condition of the constancy of the quantity of water re- 
quires that 

r^W^B^ — EB^ +fv,dA, — Cv.clA, = (215) 




Coast 



Watei Scjrfac 




BoTVom 



Fig. 19. Volume of water included in part by two surfaces of flow from the 
depth 2/j of minimum salinity to a depth ,i/„ used in determining the velocity 
of upwelling from salinity. 

where (dA.^) is an element of area of the vertical face of the prism 
next to the coast, (dA^) is an element of the other parallel face, and 
Fg and V^ are the corresponding horizontal velocities. 

Similarly, in order that the total amount of salts may remain 
constant, 

r^W,S.B. +j'v,S,dA,— fv,S,dA, = (216) 

where S^ and S^ are the salinities corresponding to the elements of 
area {dA^) and (cZAJ. 



OCEAN TEMPEEATUBES 413 

Let 

O3 ^= Oj -\- AiSg 

and 

8, = S, + ^S, (217) 

where <Si is the constant mean salinity for the prisniatio volume from 
the surface to the depth y, and ASg and AS^ are variable increments. 
Then equation (216) becomes 

— fv,{AS,)dA,- fv,{AS,)dA, = 0, (218) 

and substituting the value of 

i^fv,dA,-fv,dA:,^ 

from equation (215) we have 

V{A8')dy 

W,= ^ ^- ^ (219) 

r,{8, — 8,) r,{S,~8,) 

where (A»S") is defined on page 411, and finally, substituting for V 
the value given by equation (208) 



w,=- -^-^ 



VJ{z) j { AS' )€-"» CO J ^^ay\du 



r,(S,— SJ rA8,-S,) (220) 

If the depth of the upper section is at the level y^ we must sub- 
stitute y., for 2/1 and r, for t\ in equation (220), which then becomes 
identical with equation (211). But in equation (220) y^ can have 
any value between the limits, zero and y,, where y„ is the depth of 
minimum salinitj', and estimates of the velocity based on different 
values of y, should give the same result. Some divergence of these 
values in any actual case is to be expected, since the different esti- 
mates are based on different observations that are subject to errors 
of measurement and since the actual relation of the velocity to depth 
may differ from the theoretical relation (p. 403). 

In table 18, where y„=: 324000 (p. 404) and —E for the latitude 
of San Diego is .0754 meters per month (Schmidt, 1915, p. 121) are 
presented the results based upon the mean value of {AS'), that i.s, 
half the value entered in table 17, the mean annual salinities as shown 
by plate 11 and table 3 (McEwen, 1916) and the values of t\ and 
/(lO) from tables 13 and 14. 



414 



MISCELLANEOUS STUDIES 





h 


ICfN-^ClGCCOCC-^U^C^ 


COOGOOOCO^UOCDO^ 
']' 1 1 1 1 1 1 1 1 1 


Vcfiz) 


{AS')e-''ii cos {^-ay\ly 

o 


O=0t^00-*02C<5(NCO 
OC0C000CDCD':0t^^»O 


r, (Sz-ST) 


.05 


(AS')e-"!'cosn -0.1/ jrfy 

o 


IOCOC01^I^I--C-100C^ 

^(MCliOOlOGOOO-^CO 

coooooooooocc 


1 {AS' )e-'"-' cos (j - wi) ibj 


C0-^00^05C:OOC0O 


1 


1? 

1 


'^(N'-(OiCOI><Nt^t^iO 


'j^ 1 i 1 1 1 1 1 1 1 


1 




(N'^^!NC^'^^(NC^^c^'^^(N 


C 






1 


CO 

co^ooot^co»OTt<Tj4(ro 

^^^ooooooo 


1 1 1 1 1 1 1 1 1 1 


\^ 


lOiOOOiCOiCOOrt^O^ 


cococococococccccoco 
cocococococococococo 






s 


CCC001(MtOOO^'<*<(^0 
1-H 1— < .— 1 c^ C>1 c^ cc 



OCEAN TEMrEHArUEES 415 

Except f(ir tli(> first two values of y^ near the surface, where the 
water is most disturbed, and for the hirgest value of y„ where the 
diiference {S„ — i?,) is so small that it is subject to the largest pro- 
portional error, the computed values of the velocity W^ shown in the 
last column are in good agreement. And the mean of the central 
values, which are subject to the least error, is about — 35, which is 
the best estimate from the available data and agrees well with the 
values — 31 and — 53 found before, page 408. 

Conclusion 

In the case of no average flow of the water the form of a function 
giving the rate of gain of heat and of another giving the rate of loss 
of heat from a small volume of water at a given latitude and depth, 
was developed from a few simple assumptions, suggested by laboratory 
experiments as well as field observations. Equating the sum of these 
two expressions to the product of the specific heat by the volume by 
the rate of change of temperature resulted in a differential equation 
whose solution gave the temperature from the surface to a depth of 
ten meters as a known function of time, depth, latitude, and certain 
phj'sical constants, under the conditions of no average flow of water. 

From observations on the relation to latitude of the mean animal 
surface temperature and the annual temperature range and the relation 
to latitude of the mean annual solar radiation and its annual range, all 
of the physical constants of the formula were computed. 

The lag between the time of the temperature maxima and minima 
and tlie time of the maximum and minimum values of the solar radia- 
tion deduced from these constants agreed well with the observed value. 
Also the mean monthly temperature at a region whose mean annual 
temperatures agree well with the normal value for the latitude, that 
is, the value corresponding to no average flow, would be expected to 
agree with those computed from the ftu-mula for normal temperature. 
A comparison of .such computed and observed temperatures for a 
series of latitudes from 20° N to 40° N indicated a very satisfactory 
agreement. 

If the rate of change of temperature due to some factor not in- 
cluded in the above reasoning is known tliis quantity can be added 
to the differential equation already derived. Since all of the constants 
of the original differential equation are known the solution of the 
modified equation will give the temperature due to the new factor. 



416 MISCELLANEOUS STUDIES 

If, for example, there is a flow of the water, the rate of flow multiplied 
by the temperature where the water enters a given element of volume 
gives the rate at which the heat is carried into the volume. The rate 
at which the heat leaves the volume, computed in the same way, 
subtracted from the rate at which it enters gives the rate of change 
of heat in the volume due to the corresponding ocean current, whether 
horizontal or vertical. A term expressing this rate of change of heat 
in the case of a horizontal current was added to the differential 
equation, and the solution furnished a means of estimating the magni- 
tude of horizontal currents from surface temperatures witliout con- 
sidering the causes of the currents. 

Numerical applications of this formula to a region of the North 
Pacific off the California coast and of the North Atlantic off the 
African coast gave estimates of the horizontal flow in good agreement 
with direct observations and with what would be expected from the 
observed wind velocity. 

^ Conclusive evidence of the presence of cuiTents directed upward 
from the bottom along the California coast which cause reduction in 
temperature has been published before; but to test this conclusion 
further it was assiuned that the reduction of the temperature of the 
coastal water was due entirely to the upwelling of deep water, and 
the temperature distribution at depths exceeding 40 meters was 
assumed to result from a flow of heat according to Fourier's well 
known conductivity equation, in which a term expressing the rate of 
loss of heat due to upwelling was added. The formal solution of this 
equation contained certain physical constants whose evaluation re- 
quired the observed monthly temperatures at a series of depths. Our 
temperature data for a deep water region twenty miles offshore from 
San Diego were sufficient for making approximate estimates of all of 
the constants, of which the velocity of upwelling and the term corre- 
sponding to conductivity are of special interest. The latter constant 
depends largely upon the eddy motion, or alternating circulation, 
which tends to mix the water and has been called eddy conductivity or 
Mischungsintensitat, and was fovind in this case to be several thousand 
times the laboratory value. In dealing with salinities the same 
formula can be vised; and a similar constant appears, which also 
depends largely on the mixing motion of the water, and would be 
expected to have practically the same value as that determined from 
temperatures. Our salinitiy data, though not so complete as the 
temperature data, confirmed tliis conclusion and gave approximately 



OCEAN TEMPEEATUEES 



417 



the same velocity of upwelling. Moreover, in applying hydrodynamieal 
equations to problems of oceanic circulation the coefficient of viscosity 
must be replaced by another constant depending on the eddy, or 
turbulent motion, and having a nuich greater value than the laboratory 
vahie obtained from observations on a slow laminar flow free from 
irregular motions. Similar results have also been found by G. I. 
Ta.ylor in certain recent studies of the temperature, water vapor, and 
velocity in the atmosphere. The results of laboratory experiments 
and theories based on them were helpful but could not provide the 
numerical values requi red ; iu each case field observations were neces- 
sary. Furthermore, since the eddy conductivity, or Mischungs- 
inten-sitdt, is not a physical constant of the substance, sea water or 
air, but depends upon the intensit.y and character of the circulation, 
its value will vary accordingly. The following approximate values of 
these constants, the coefficient of viscosity, diffusion, and conductivity 
under laboratory conditions and estimated from field observations in 
the ocean and the atmosphere, illustrate the great differences between 
field and laboratory conditions. 



Table 19 

Estimates of the coefflcients of viscosity, diffusion, and heat conductivity made 

from field observations in the ocean and atmosphere compared 

tvith values obtained in laboratory experiments 



Sea Water 



Observ-er 


Coefficient 


Laboratory value 
in c. g. s. units 


Value from field 

obsen-ations in 

c. g. s. units 


Ratio of the field 
to the laboratory 
value 


Ekman 


Vi.scosity' 


.014 


217 


15,500 


Jacob.sen 


Diffusion 


.0000125 


.3 to 11.4 


24,000 to 
320,000 


McEwen 


Diffusion 


.0000125 


40 




McEwen 


Conductivity^ 


.0012 


30 


25,000 



Air 



Taylor 
Taylor 



Viscosity' 
Conductivity^ 



.13 

.20 



770 to 6,900 
570 to 3,400 



6,000 to 50,000 
3,000 to 17,000 



' The laboratory value of the "kinetic coefficient" of viscosity, or the coeflficient of viscosity 
divided by the density, is given since it is the constant in the equations of motion, which is 
formally equivalent to the one given by field observations. 

= The laboratory value of the thermometric conductivity is given since that is the constant 
in the equation of heat conductivity, which is formally equivalent to the one given by field 
observations. 



The estimation of the effect of upwelling on the surface tempera- 
ture made necessary the consideration of results obtained for depths 



418 MISCELLANEOUS STUDIES 

below the 40 meter level and the solution of the original differential 
equation for surface temperatures after adding a term giving the rate 
of temperature change due to upwelling. The monthly values deduced 
in this wa.y for the San Diego region agree very well with those 
afforded by the observations. 

From the magnitude of the vertical velocity found from tempera- 
tures and from certain results deduced from Ekman's hydrodynamical 
theory, the distribution of the horizontal and vertical velocity of the 
water in a vertical plane perpendicular to the coast was deduced and 
represented graphically. 

An independent estimate of the velocity of upwelling made from 
the distribution of salinities in the upper 30 meter layer and of the 
rate of evaporation at the surface agreed well with the other two 
estimates. Moreover, the estimates of the velocity of upwelling from 
the temperature or salinity distribution did not depend upon the 
cause of the upwelling ; Imt it is an interesting fact that such a vertical 
current would be expected along the California coast from Ekman's 
hydrodynamical theory. 

I wish to express my obligation to Dr. W. E. Ritter of this institu- 
tion, and to my laboratory assistant, ]Mr. Nephi W. Cummings, for 
his aid in making the computations and for his suggestions while 
preparing the manuscript. 

Transmitted June 26, 1918. 
Scripps Institution for Biological Ecscarch 
of the University of California, 
La JoUa, California. 



OCEAN rKMPEKA'VVEES 419 



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1894. Presidential address. Section E, Geography. Rept. Brit, .\ssoc. Adv. 
Sei. 

WiNKELMANN, A. 

1906. Handbueh der Physik. (Leipzig, Barth), 3, xiv + 1178, 206 figs, in 
text. 

ZOPPRITZ, K. 

1878. Hydrodynamische Probleme in Eeziehung zur Theorie der Meeres- 
stromungen. Wiedenianns Anrialen, 3, 582-607. 



CHANGES IN THE 
CHEMICAL COMPOSITION 
OF GRAPES DURING RIPENING 



BY 

F. T. BIOLETTI, W. V. CRUESS, and H. DAVI 



[University of California Publications in Agricultural Sciences, Vol. 3, No. 6, pp. 103-130] 



CHANGES IN THE 

CHEMICAL COMPOSITION OF GRAPES 

DURING RIPENING 

BY 

F. T. BIOLETTI, W. V. CRUESS, and H. DAVI 



The investigations reported in this paper were undertaken to 
determine the changes in chemical composition of vinifera varieties 
of grapes in California during the growing and ripening stages. A 
survey of the literature indicated that, although tlie subject had been 
quite fully investigated in Europe with vinifera varieties and in 
America with the native varieties, very little had been published iipon 
the ripening of vinifera varieties under California Conditions. A 
great many analyses of different varieties of grapes have been made 
by chemists of the University of California Experiment Station, nota- 
bly by G. E. Colby, and are reported in the publications of this station.' 
A paper by G. E. Colby^ gives data upon the nitrogen content of a 
number of varieties of ripe vinifera grapes. Most of the analyses, 
however, do not show the changes in composition during ripening. 

Of the more recent European investigations^ some deal with the 
changes in general composition, others are confined to a discussion of a 
single component, such as sugar, or coloring matter, or acid principles. 

The changes in composition of American varieties of grapes during 
ripening have been studied quite thoroughly by "W. B. Alwood* and 
his associates. These investigations gave particular attention to the 



1 Hilgard, E. W., The composition and classification of grapes, musts, and 
wines. Rept. of Viticultural Work, Univ. Calif. E.^cper. Sta. Rep., 1887-93, pp. 
3-360. 

2 Colby, G. E., On the quantities of nitrogenous matters contained in Cali- 
fornia musts and wines. Ibid., pp. 422-446. 

3 KcHiofer, W., The gi-ape in the various stages of maturity; trans, by E. 
Zardetti. Gior. Vin. Ital., vol. 34 (1908), no. .30, pp. 475-477. 

Barberon, G., and Changeant, F., Investigations on the development and 



(103 1 



424 MISCELLANEOUS STUDIES 

increase in sugar content and changes in acidity during the period 
in which the grapes were under observation. Alwood and other mem- 
bers of the Bureau of Chemistry, United States Department of Agri- 
culture, have also published a ninnber of reports* on the general 
composition of American varieties of grapes as affected by season, 
locality, etc. 

The most notable changes taking place during ripening were found 
by the European and American investigators mentioned above to be : 
(1) increase in total sugar ; (2) decrease in ratio of glucose to fructose ; 
(3) decrease in total acid; (4) increase in ratio of cream of tartar to 
total acid due to decrease in total acid ; (5) decrease in tannin ; and (6) 
increase in coloring matter. The cream of tartar and protein change 
very little in percentage during ripening, although, according to the 



composition of varieties of grapes in Abraon-Durso. Ann. Soc. Agr Sci. et Ind., 
Lyon (8), vol. 1 (1903), pp. 97-159. 

Laborde, J., The transformation of the coloring matter of grapes during 
ripening. C. E. Acad. Sci. (1908), vol. 17, pp. 753-755. 

Martinand, V., On the occurrence of sucrose and saccharose in different parts 
of the grape. C. R. Acad. Sci. (1907), vol. 24, pp. 1376-79. 

Boos, L., and Hughes, E., The sugar of the grape during ripening. Ann. 
Falsif. (1910), vol. Ill, p. 395. 

Bouffard, A., Observations in regard to the proportion of sugar during ripen- 
ing. Ann. Falsif. (1910), vol. JII, pp. 394-5. 

Zeissig, Investigations on the process of ripening on one-vear-old grape wood. 
Ber. k. Lehranst. Wien, Obst-u. Garten-bau (1902), pp. 59-64. 

Koressi, F., Biological investigations of the ripening of the wood of the 
grape. Rev. Gen. Bot., vol. 13 (1901), no. 149, pp. 19,3-211; no. 150, pp. 251-264; 
no. 151, pp. 307-325. 

Brunet, R., Analvsis and composition of the grape during ripening. Rev. 
de Viticulture, vol. 37, pp. 15-20. 

Garina, C, Variations in the principal acids of grape juice during the process 
of maturing. Canina, Ann. R. acad. d 'agricultura di Torino, vol. 57 (1914), 
p. 233. Cf. Ann. Chim. applicata, vol. 5 (1914), pp. 65-6, See also Ann, r, acad. 
d 'agr. di Torino, vol. 57, pp. 233-90. 

Baragolia, W. I., and Godet, C, Analytical chemical investigations on the 
ripening of grapes and the formation of wine from them. Landw. Jahrb., vol. 
47 (1914), pp. 249-302. 

Riviere, G., and Bailhache, G., Accumulation of sugar and decrease of acid 
in grapes. Chem. Abs. Jour. (1912), p. 1022; Jour. Soc. Nat. Hort. France (4), 
pp. 125-7; Bot. Cent., 1912, pp. 117, 431. 

Pantanelli, Enzyme in must of overripe grapes. Chem. Abs. Jour., vol. VI 
(1912), p. 2447. 

4 Alwood, W, B., Hartmann, J. B., Eoff, J. R., and Sherwood, S. F., Develop- 
ment of sugar and acid in grapes during ripening. U. S. Dept. Agrie. Bull. 335, 
April 11, 1916. 

The occurrence of sucrose in grapes. Jour. Indust., vol. II, Eng. Chem. 

(1910), pp. 481-82. 

Sugar and acid content of American native grapes. 8th Inter. Cong. 

Appl. Chem. (1912), Sect. Vla-XIv, pp. 33, 34. 

Enological Studies: the chemical composition of American grapes grown 

in Ohio, New York, and Virginia. IT. S. Dept. Agric. Bur. Chem. Bull. 145, 1911. 

Crystallization of cream of tartar in the fruit of grapes. U. S. Dept. 

Agric. Jour. Agric. Research (1914), pp. 513, 514. 

Alwood, W. B., Hartmann, B. G., Eoff, J. R., Sherwood, S. F., Carrero, J, C, 
and Harding, T. J., The chemical composition of American grapes grown in the 
central and eastern states. XT . S. Dept. Agrie. ( 1916) Bull. 452. 



11041 



CHEMICAL COMI'OSITION OF Gl^.tl'IiS 425 

investigations rcferreti to, there is a slight increase in both of these 
constituents. 

In the investigations reported in the present paper, particular 
attention was given to increase in total solids and sugar, decrease in 
total acid, and changes in protein and cream of tartar in the must or 
juice of the grapes. The ripening of the leaves was traced by noting 
the changes in starch, sugar, acid, and protein content. 

Sampling. — During 1914 and 1915 samples of fruit were taken 
from the time the grapes had reached full size but were still hard and 
green until they had become overripe. During 1916 the first samples 
were taken shortly after the berries had set and before the seeds had 
formed. The last samples were taken when the grapes had become 
overripe. Samples of leaves were also taken in 1916 on the same 
dates that samplings of the grapes were made. The samples were 
taken at intervals of approximately one week. They were in all cases 
taken from the experimental vineyard at Davis.'* 

Five-pound samples of grapes were used. The grapes were picked 
from the first crop, except in 1914, when a comparison of the ripening 
of first and second crops was made. An ordinary five-pound grape 
basket was filled with leaves at each sampling. The samples of grapes 
and leaves were shipped from the vineyard to the laboratorj' at 
Berkeley, where the grapes were placed in an Enterprise fruit crusher 
and pressed. The juice was sterilized in bottles at 212° F. The leaves 
were ground in an Enterprise food chopper and sterilized at 212° F 
in wide mouth, air tight bottles. The samples were then reserved for 
chemical examination. 

In 1914 it was found that there was considerable irregularity in 
the variation of samples from week to week. For example, instead 
of an increase of total solids during the periods between samplings, a 
slight decrease was found in a few samples. During the 1915 season 
it was therefore considered of interest to note what effect certain 
factors might have upon the composition of samples taken on the 
same date. 

1. Effect of Age of Vine. The entire first crop from three large 
old vines and from three small young vines, all of the Muscat variety, 
was picked, crushed, and pressed. Analyses of the juices were made 
with the following results : 



^ The authors wish to express their appreciation of the assistance of F. C. 
Flossfeder, of the University Farm at Davis, who gathered most of the samples 
reported upon in this paper. 



11051 



426 MISCELLANEOUS STUDIES 

Table 1 — Effect of Age of Vine on Balling and Acid of Must of Muscat 

Grapes 

Vine Balling Acid 

Small, no. 1 24.7 .67 

Small, no. 2 27.7 .49 

Small, no. 3 27.6 .67 

Large, no. 1 22.0 .88 

Large, no. 2 23.5 .75 

Large, no. 3 23.6 .76 

Average, small 26.7 .61 

Average, large 23.0 .81 

Difference 3.7 — .20 

The results show rather strikingly that young vines ripen their 
fruit earlier than do mature vines. This fact makes it essential that 
samples, to be comparative, must be taken from vines of the same age. 

2. Comparison of Grapes from North and South Sides of Vines. 
The whole first crop from three large Muscat vines was picked. The 
bunches from the north and south sides of each vine were kept sep- 
arate. The}- were crushed, pressed, and analyzed for Balling and acid 
content. 

Table 2 — Comparison of B.vlling and Acid of Juice from Grapes Picked from 
North and South Sides of Vines 

Vine and side of vine Balling Acid 

1-N 21.3 .92 

as 22.7 .84 

2-N 23.5 .81 

2-S 23.5 .80 

3-N 23.1 .81 

3-S 24.1 .71 

Average, N side 22.63 .85 

Average, S side 23.43 .78 

Difference 80 —.07 

The tests indicate that grapes located on the south side of the vine 
ripen more rapidl.y than those on the north side. This difference is 
apparently due to the fact that the south side of the vine receives 
more heat than the north side. 

3. Effect of Location of Bunch on Cane. Grapes of first crop, from 
canes showing two bunches each, were picked and the bunches from 
near tlie bases of the canes kept separate from those near the tip of 
the cane. They were crushed, pressed, and analyzed for Balling and 
acid. 



[1061 



CHEMICAL COMPOSITION OF GRAPES 427 

Table 3 — Effect of Location op Bunch on Cane 

Nearest base of cane Nearest tip of cane 

Vine Balling Acid Balling Acid 

Muscat, no. 1, cane 1 25.1 .73 23.7 .83 

Muscat, no. 1, cane 2 25.6 .79 24.8 .80 

Muscat, no. 2, cane 1 25.1 .85 24.6 .87 

Muscat, no. 2, cane 2 25.2 .78 24.7 .85 

Muscat, no. 3, cane 1 23.0 .79 22.6 .82 

Muscat, no. 3, cane 2 24.5 .73 23.8 .73 

Muscat, no. 4, cane 1 ., 24.2 .90 25.2 .90 

Muscat, no. 4, cane 2 24.5 .68 23.8 .83 

Tokay, cane 1 21.2 .67 21.2 .80 

Tokay, cane 2 23.0 .63 22.4 .76 

Sultanina, cane 1 23.3 .61 22.3 .62 

Sultanina, cane 2 22.5 .61 23.0 .63 

Sultana, cane 1 23.2 .78 21.6 .70 

Sultana, cane 2 21.1 .90 20.0 1.20 

Palomino, cane 1 25.1 23.5 

Palomino, cane 2 22.0 23.7 

Means 24.9 .75 23.1 .81 

The data indicate that bunches at the base of the cane ripen in most 
cases more rapidly than those near the tip. although this relation does 
not always hold and may be reversed in some instances. 

4. Variation in Balling Degree of Must from Bunches of Similar 
Appearance and Size from Same Vineyard and Gathered on Same 
Date. A five-pound basket of grapes of first crop and selected for 
similarity of color, .size of bunch, and general appearance was picked 
from each of a number of vines in the same vineyard. Vines of 
similar size and appearance were chosen. Several varieties were rep- 
resented in the experiment. Tests of Balling degree only were made. 

Table 4 — Variation in Balling in Must From Grapes of Same Variety Picked 
Prom Different Vines of Similar Appearance 



Variety 


Vine 
number 


Balling 


Mean 
Balling 


Maxiimira 
variation 


Cornichon 


3 


14.5 






Cornichon 


6 


15.0 






Cornichon 


9 


14.2 






Cornichon 


11 


14.7 






Cornichon 




16.1 


14.9 


1.9 


Emperor ■ 

Emperor 

Emperor 


10 
11 
13 


12.0 
14.5 

1.5.2 






Emperor 
Emperor 


14 

17 


i5.n 

15.0 


UA 


3.5 


Malaga 
Malaga 


5 
6 


18.5 
17.2 







[1071 



•128 



MISCELLANEOUS STUDIES 



Table 4 — {Continued) 





Vine 




Mean 


Maximum 


Variety 


number 


Balling 


Balling 


variation 


Malaga 


7 


19.7 






Malaga 


9 


18.5 






Malaga 


11 


19.2 


18.6 


2.0 


Muscat 


* 


21.7 






Muscat 


* 


21.1 






Muscat 


• 


20.9 






Muscat 


« 


21.5 






Muscat 


♦ 


21.7 


21.4 


.8 


Palomino 


3 


19.5 






Palomino 


4 


21.0 






Palomino 


6 


21 2 






Palomino 


7 


20.7 






Palomino 


9 


18.8 


20.2 


2.4 


Sultanina 


» 


22.5 






Sultanina 


# 


21.5 






Sultanina 


* 


18.7 






Sultanina 


* 


22.0 






Sultanina 


* 


22.6 


21.5 


3.9 


Tokay 


* 


19.8 






Tokay 


* 


19.3 






Tokay 


» 


18.7 






Tokay 


* 


20.7 






Tokay 


* 


19.5 


19.6 


2.0 


Pedro Zumbon 


7 


21.5 






Pedro Zumbon 


4 


21.2 






Pedro Zumbon 


6 


20.6 






Pedro Zumbon 


3 


18.5 






Pedro Zumbon 


5 


19.8 


20.3 


3.0 


Emperor 


15 


18.1 






Emperor 


8 


15.8 






Emperor 


14 


16.2 






Emperor 


9 


16.8 






Emperor 


16 


16.3 


16.6 


2.3 


Cornichon 


4 


17.3 






Cornichon 


9 


16.3 






Cornichon 


10 


17.9 






Cornichon 


11 


17.8 






Cornichon 


13 


18.0 


17.5 


1.7 


Malaga 


4 


18.3 






Malaga 


5 


20.4 






Malaga 


6 


20.0 






Malaga 


8 


20.1 


19.7 


1.8 



Mean variation, six ripest varieties 2.32 

Mean variation, six least ripe varieties 2.20 

Average variation, whole series 2.30 



' Adjacent vines. 



[1081 



cuEMivAi. vvMroanios of ghapks 429 

The data illustrate the difficulty of selecting five-pound lots of the 
same variety that will represent average samples. 

5. Effect of Location of Berries on the Bunch. All of the bunches 
of the first crop were taken from two Muscat vines. The bunches 
were cut into top and bottom halves. These lots were cruslied sep- 
arately, pressed, and the juices analyzed. 

T.A.BLE 5 — Effect of Location of 'Berries on Bunch 

Sample Balling Acid 

Vine no. 1, stem end of bunch 23.6 .76 

Vine no. 1, apical end of bunch 22.7 .87 

Vine no. 2, stem end of bunch 21.3 .92 

Vine no. 2, apical end of bunch 21.3 .93 

The results show that considerable variation in composition of the 
berries may exist within the same bunch. 

6. Effect of Thoroughness of Pressing. About ten pounds of Mus- 
cat grapes were crushed and lightly pressed. The pulp and skins left 
from this pressing were then thoroughly crushed and pressed a second 
time. The juices from the two lots were analyzed separately. 

Table 6 — Effect of Thoroughness of Pressing 

Sample Balling Acid 

First pressing 22.8 .78 

Second pressing 22.8 .79 

There was practically no difference between the juices from lightly 
and thoroughly pressed grapes of the same lot. 

The data from the above six tests indicate that it is a very difficult 
matter to select grapes that will represent a fair average sample of 
the grapes to be studied. The size and age of the vine, the side of 
the vines, the location of the bunch on the cane, and individual vines, 
all affect the composition of the juice from the grapes very materially, 
and these factors should be taken into account when samples are 
taken. 

Preservation of Samples and Preparation for Analysis. — In 1914 
the samples of juice were preserved with HgCl,, 1 :1000. In 1915 and 
1916 the samples were sterilized at 100° G. Before analysis the bottles 
were heated to 100° C for an hour to dissolve any cream of tartar which 
might have separated. The juices were filtered before analysis. Con- 
siderable coagulation of dissolved solids took place during sterilization. 



1 109 I 



430 MISCELLANEOUS STUDIES 

Methods of Analysis. — The samples were analyzed by the methods 
in use in the Agricultural Chemistry Laboratory and the Nutrition 
Laboratory of this station. A brief description of the methods follows : 

1. Total Solids. The juice was filtered clear and cooled below 
15° C. The specific gravity was determined by a pyenometer at 
15?5 C. The corresponding total solids, or extract, was found from 
Windisch's tables in Leach's Food Anahjsis, page 697. This table 
gives the extract as "grams per 100 grams"; that is, per cent by 
weight. To calculate the corresponding grams per 100 c.c, the per 
cent by weight was multiplied by the specific gravity. This gives a 
figure not very much greater than grams per 100 grams in juices of 
low specific gravity, but gives a figure as much as 2 per cent greater 
where the total solids are much above 20 per cent. The two methods 
of reporting total solids has in the past led to much unnecessary 
confusion. It is therefore urged that the reader bear in mind the 
distinction between the two methods when reading the discussions in 
this paper or examining the curves. 

2. Sugar. The sample was filtered ; an aliquot was treated with 
lead acetate ; diluted to mark ; filtered ; lead removed witli anhydrous 
Na„CO..,, and the sugar determined in an alicjuot by the gravimetric 
method, using Soxhlot's modification of Fchling's solution. The Cu.^O 
was weighed directly after drying at 100° C. The corresponding 
sugar as invert sugar was obtained from Munsou and Walker's table 
in Leach's Food Anahjsis. The grams of invert sugar ]ier 100 c.c. 
found in this way was divided by the specific gravity of the must to 
obtain the corresponding grams per 100 grams of juice. 

3. Total acid was determined by titration of a 10 c.c. sample with 
N/10 NaOII, using phenolphthaleiii as an indicator, and is reported 
as tartaric acid, grams per 100 c.c. 

4. Cream of tartar was estimated by a method suggested by Pro- 
fessor D. R. Hoagland of the Division of Agricultural Chemistry. 
Ten c.c. of the juice was incinerated at a low heat in a muffle furnace 
until well carbonized, but not to a white ash. (Excessive heating 
results in loss of K by volatilization.) The KXO3 formed by incin- 
eration was leached out with hot water and a known excess of N/10 
HCl added. This was titrated back with N/10 NaOH, using methyl 
orange as an indicator. The K.CO3 is obtained by difference and 
calculated back to cream of tartar, assuming that all of the KoCO, is 
formed by the oxidation of cream of tartar, KH(C^H^O,;)- It is 



I II" I 



CHEMICAL COMPOSITION OF GRAPES 431 

reported as grams KI^C^H^O,,) per 100 c.c, and also as tartaric 
acid. 

5. Free Tartaric Acid was obtained by difference between total acid 
and cream of tartar calculated as tartaric acid. It is reported as 
grams per 100 c.c. 

6. Protein in the juice was determined by the usual Kjeldahl- 
Gunning method upon a 10 c.c. sample. It is reported as grams per 
100 c.c. 

7. Moisture in the leaves was determined by drying the sample at 
100° C. 

8. Sugar in the leaves was estimated by leaching the dried sample 
with cold water and determining sugar by the gravimetric Pehling 
method in the filtrate. 

9. Starch in the leaves was determined by hydrolysis of the dried 
ground sample with dilute HCl at 100^ C, followed by filtration and 
the usual gravimetric Fehling method for juice described above. 

10. Protein in the leaves was determined by the Kjeldahl-Gunning 
method on .5 gram samples. 

11. Acid in the leaves was estimated by leaching in hot w-ater and 
titrating in the presence of the leaves, using litmus paper as indicator. 

Analyses of Musts from Grape-Ripening Samples, 191 i, lOl'j, 1916. 
The data from the analyses have been assembled in the following 
tables. Owing to the size of the tables, abbreviations have been 
necessary for the headings of the columns. 

EXPLAXATIOXS OP FeaDIXGS OF TABLES 

1. Sp. gr. ^ Specific gravity at 15?5 C. 

2. T. S. G. = Total solids in grams per 100 grams. 

3. T. S. C. = Total solids in grams per 100 c.c. 

4. S.G.^ Sugar in grams per 100 c.c. 

5. S. I. ^ Sugar in grams per 100 grams. 

6. Tl. A. = Total acid in grams per 100 c.c. 

7. C.T. = Cream of tartar in grams per 100 c.c. 

8. C. T. T. = Cream of tartar as tartaric acid, grams per 100 c.c. 

9. T. A. = Total free acid as tartaric obtained by subtracting cream of tartar 
as tartaric from total acid as tartaric. 

10. P. ^Protein, grams per 100 c.c. 

11. S. = Sum of sugar, cream of tartar, tartaric acid, and protein in grams 
per 100 c.c. 

12. T. S. — S. = Total solids (T. S. C.) — S (preceding column). 



run 



432 



MISCELLANEOUS STUDIES 



Table 7 — Grape Ripening Tests, 1914 
(Grapes from Davis) 



Malaga 


























First crop: 


























Variety 
and date 


1 
Sp- gr. 


O 

T. S. G, 


3 

, T, S. C 


4 
, S. 6, 


5 
S, I. 


6 

Tl, A, 


7 
C. T, 


8 
C.T.T 


9 
, T, A, 


10 

p. 


11 
S. 


12 
T, S, S, 


Aug. 19 


1.0396 


10.25 


10.65 


7.32 


7.04 


2.78 


.35 


.13 


2.65 


.21 


10.53 


.12 


Aug 26 


1.0413 


10.69 


11.13 


7.84 


7.53 


2.65 


.36 


.14 


2.51 


.25 


10.96 


.17 


Aug. 26 


1.0595 


15.42 


16.33 


13.37 


12.62 


.77 


.48 


.19 


.58 


.55 


14.98 


1.41 


Aug. 26 


1.0613 


15.87 


16.84 


14.31 


13.50 


1.46 


.31 


.12 


1.34 


.33 


16.29 


.55 


Aug. 26 


1.0694 


18.01 


19.25 


16.59 


15.52 


1.00 


.36 


.14 


.86 


.38 


18.19 


1.06 


Aug. 31 


1.0732 


19.00 


20.39 


17.65 


16.45 


.87 


.55 


.22 


.65 


.45 


19.30 


1.09 


Sept. 23 


1.0736 


19.10 


20.50 


17.83 


16.60 


.74 


.38 


.15 


.59 


.52 


19.32 


1.18 


Oct. 5 


1.0965 


25.12 


27.54 


24.89 


22.70 


.72 


.50 


.20 


.52 


.57 


26.48 


1.06 


Second crop: 
























Aug. 10 


1.0213 


5.51 


5.62 


2.07 


2.03 


3.22 


.23 


.09 


3.13 


.17 


5.60 


.02 


Aug. 31 


1.0495 


12.82 


13.45 


9.58 


9.13 


2.51 


.40 


.16 


2.35 


.28 


12.61 


.84 


Sept. 14 


1.0532 


13.78 


14.51 


11.89 


11.30 


2.07 


.37 


.15 


1.92 


.31 


14.49 


.02 


Sept. 23 


1.0670 


17.43 


18.60 


15,29 


14.33 


1.54 


.50 


.20 


1.35 


.29 


17.43 


1.17 


Sept. 23 


1.0869 


22.59 


24.,55 


22.04 


20.19 


1.07 


.45 


.18 


.89 


.41 


23.79 


.76 


Oct. 5 


1.0930 


24.20 


26.45 


23.90 


21.87 


.94 


.48 


.19 


.75 


.41 


25.54 


.91 


Tokay 


























First crop: 


























Aug. 2 


1,0454 


11.75 


12,28 


8.73 


8.35 


2.63 


.46 


.18 


2.45 


.32 


11.96 


.32 


Aug. 10 


1.0624 


16.08 


17.08 


14,28 


13.44 


1.56 


.45 


.18 


1.38 


.27 


16.38 


.70 


Aug. 19 


1.0682 


17.69 


18.90 


15.94 


14.92 


1.32 


.45 


.18 


1.14 


.27 


17.80 


1.10 


Aug. 3i 


1.0849 


22.09 


23.97 


21.87 


20.16 


.63 


.59 


.23 


.40 


.40 


23.26 


.71 


Sept. 4 


1.0865 


22.49 


24,44 


22.21 


20.44 


.77 


.43 


.17 


.60 


.32 


23.56 


.88 


Sept. 4 


1.0912 


23.72 


25.88 


23.44 


21.48 


.59 


.64 


.25 


.44 


.41 


24.93 


.95 


Sept. 23 


1.0937 


24.38 


26.66 


24.15 


22.08 


.58 


.49 


.19 


.30 


.39 


25.33 


1.33 


Oct. 14 


1.0991 


25.80 


28.36 


25.55 


23.25 


.45 


.54 


.21 


.24 


.45 


26.78 


1.58 


Oct. 14 


1.1000 


26.04 


28.64 


25.78 


23.44 


.52 


.58 


.23 


.29 


.58 


27.23 


1.41 


Second crop 


























Aug. 19 


1.0657 


17.04 


18.16 


15.03 


14.10 


1.91 


..50 


.20 


1.70 


.32 


16.55 


.61 


Sept. 14 


1.0701 


18.19 


19.47 


16.68 


15,59 


1.29 


.52 


.21 


1.11 


.33 


18.64 


.83 


Sept. 23 


1.0769 


19.95 


21.48 


19.22 


17.85 


1.01 


.48 


.19 


.82 


.40 


20.92 


.56 


Oct. 14 


1.0911 


23.70 


25.86 


23.43 


21.47 


.69 


.60 


.24 


.45 


.40 


24.88 


.98 



Table 8 — Grape Ripening Tests, 1915 
(Grapes from D.ivis) 



Cornichon 


























Variety 
and date 


1 
Sp. gr. 


2 
t, S, G, 


3 
T. S. C. 


4 
S, G. 


5 
S, I. 


6 

Tl, A, 


7 
C, T, 


8 
C. T, T. 


9 
T, A, 


10 

P, 


11 

S, 


12 

T. S. S. 


Aug. 22 


1.0324 


8.38 


8.65 


3.99 


3.86 


3.05 


.58 


.23 


2.82 


.38 


7.77 


.88 


Sept. 1 


1.0514 


13.31 


13.99 


10.70 


10.18 


1.62 


.61 


.25 


1.37 


.42 


13.10 


.89 


Sept. 15 


1.0688 


17.85 


19.08 


15.94 


14.91 


.97 


.70 


.28 


.69 


.43 


17.76 


1.32 


Sept. 22 


1.0723 


18.76 


20.12 


16.97 


15.83 


.94 


.71 


.28 


.66 


.46 


18.80 


1.32 


Sept. 29 


1.0737 


19.13 


20.54 


18,31 


17.05 


.87 


.75 


.30 


.61 


.66 


20.33 


.21 


Oct. 7 


1.0781 


20.28 


21.86 


19.41 


18.02 


.71 


.73 


.29 


.42 


.48 


21.04 


.82 


Oct. 14 


1.0843 


21.91 


23.76 


20.40 


18.81 


.78 


.68 


.27 


.62 


.66 


22.36 


1.40 


Oct. 22 


1.0873 


22.70 


24.68 


21.06 


19.37 


.75 


.78 


.31 


.44 


.46 


22.74 


1.94 



[1121 



CHEMICAL COMPOSITION OF GKAPES 



433 



Emperor 



Table 8 — (Continued) 



"Variety 
and date 


1 
Sp. gr. 


2 

T. s" G. 


3 
T. S. C. 


4 
S. G. 


5 

S. I. 


6 

Tl. A. 


7 
C. T. 


8 
C.T.T. 


9 
T. A. 


10 

p. 


11 

S. 1 


12 
. A. S 


Aug. 19 


1.0420 


10.87 


11.33 


6.96 


6.68 


2.33 


.38 


.15 


2.18 


.38 


9.90 


1.43 


Sept. 1 


1.0479 


12.40 


12.99 


9.82 


9.37 


1.89 


.40 


.16 


1.73 


.62 


12.57 


.42 


Sept. 7 


1.0560 


14.51 


15.32 


11.48 


10.87 


1.70 


.47 


.19 


1.57 


.54 


14.00 


1.32 


Sept. 15 


1.0632 


16.37 


17.40 


14.88 


14.00 


1.40 


.53 


.21 


1.18 


.54 


17.13 


.27 


Sept 22 


1.0652 


16.91 


18.01 


15.46 


14.51 


.93 


.48 


.19 


.74 


.55 


17.23 


.78 


Sept. 29 


1.0672 


17.43 


18.60 


16.37 


15.34 


.91 


.48 


.19 


.72 


.66 


18.23 


.37 


Oct. 7 


1.0744 


19.31 


20.75 


17.82 


16.59 


.79 


.58 


.23 


.56 


.51 


19.47 


1.28 


Oct. 14 


1.0765 


19.86 


21.38 


18.37 


17.06 


.79 


.59 


.24 


.56 


.63 


20.15 


1.23 


Oct. 22 


1.0792 


20.57 


22.20 


19.81 


18.36 


.75 


.63 


.25 


.49 


.66 


21.59 


.61 



Malaga 



Aug. 


19 


1.0546 


14.14 


14.91 


12.47 


11.82 


2.05 


.36 


.15 


1.90 


.75 


15.48 


.57 


Aug. 


2^ 


1.0651 


16.86 


17.96 


14.53 


13.64 


1.66 


.46 


.18 


1.48 


.90 


17.37 


.59 


Sept. 


1 


1.067S 


17.59 


18.78 


16.75 


15.69 


1.38 


.44 


.18 


1.20 


.89 


19.28 


.50 


Sept 


7 


1.0719 


18.66 


19.50 


17.00 


15.86 


1.29 


.44 


.18 


1.11 


.70 


19.25 


.25 


Sept. 


15 


1.0758 


19.68 


21.17 


18.17 


16.89 


1.21 


.62 


.25 


.96 


.70 


20.45 


.72 


Sept. 


22 


1.0760 


19.81 


21.32 


18.39 


17.09 


1.18 


.61 


.25 


.93 


.74 


20.67 


.65 


Sept. 


29 


1.0812 


21.20 


22.92 


18.48 


17.09 


1.07 


.58 


.23 


.84 


.75 


20.65 


2.27 


Oct. 


7 


1.0838 


21.78 


23.61 


21.03 


19.40 


1.07 


.65 


.26 


.81 


.73 


23.22 


.39 


Oct. 


14 


1.0970 


25.25 


27.70 


24.58 


22.41 


.59 


.83 


.33 


.26 


.88 


26.55 


1.15 



Muscat 



Aug. 19 


1.0615 


15.94 


16.92 


13.93 


13.12 


1.70 


.36 


.15 


1.55 


.70 


16.54 


.38 


Aug. 25 


1.0744 


19.31 


20.75 


17.96 


16.72 


1.21 


.62 


.25 


.96 


.62 


20.16 


.59 


Sept. 1 


1.0805 


20.91 


22.59 


19.50 


18.05 


.79 


.63 


.25 


.54 


.63 


•21.30 


1.29 


Sept. 7 


1.0827 


21.47 


23.25 


20.39 


18.83 


.76 


.65 


.26 


.50 


.66 


22.20 


1.05 


Sept. 15 


1.0917 


23.85 


26.04 


23.49 


21.52 


.96 


.58 


.23 


.73 


.58 


25.38 


.66 


Sept. 22 


1.0954 


24.14 


26.44 


24.54 


22.40 


.77 


.62 


.25 


.52 


.85 


26.53 


.09 


Sept. 29 


1.1048 


27.30 


30.16 


27.01 


24.45 


.72 


.72 


.29 


.44 


.72 


28.89 


1.27 


Oct. 7 


1.1079 


28.12 


31.15 


28.28 


25.53 


.66 


.59 


.23 


.43 


.66 


29.96 


1.19 


Pedro Zum 


ion 
























Aug. 19 


1.0555 


14.38 


15.18 


11.96 


11.33 


1.81 


.68 


.27 


1.54 


.33 


14.51 


.67 


Aug. 25 


1.0588 


15.24 


16.14 


13.77 


13.01 


1.09 


.57 


.23 


.86 


.53 


15.73 


.41 


Sept. 1 


1.0642 


16.64 


17.71 


15.61 


14.67 


.58 


.52 


.21 


.37 


.43 


16.93 


.78 


Sept. 7 


1.0693 


17.98 


19.23 


16.55 


15.48 


.84 


.48 


.19 


.65 


.73 


18.41 


.82 


Sept. 15 


1.0708 


18.37 


19.67 


18.17 


16.97 


.56 


.58 


.23 


.33 


.64 


19.72 


.05 


Sept. 22 


1.0912 


23.72 


25.88 


23.02 


21.10 


.53 


.87 


.35 


.19 


.64 


24.72 


1.16 



Sultana 

Aug. 19 
Aug. 25 
Sept. 1 
Sept. 7 
Sept. 22 1.0902 23.39 25.50 23.10 21.19 1.24 .50 



1.0673 


17.80 


19.00 


15.63 


16.64 


1.69 


.33 


1.0746 


19.37 


20.82 


17.96 


16.71 


1.44 


.37 


1.0815 


21.17 


22.90 


20.26 


18.73 


1.14 


.54 


1.0893 


23 22 


25.29 


23.02 


21.13 


.78 


.44 



Sept. 29 1.0922 23.99 26.20 24.04 



:.oi 



.80 .41 



.13 


1.56 


.32 


17.84 


1.16 


.14 


1..30 


.38 


20.01 


.81 


oo 


.92 


.50 


22.22 


.68 


.18 


.60 


.34 


24.40 


.89 


.20 


1.04 


.38 


25.02 


.48 


.17 


.63 


.42 


25.50 


.70 



[113] 



434 



MISCELLANEOUS STUDIES 



Table 8 — (Continued) 



Sultanina 


























Variety 
and date 


1 
Sp. gr. 


2 
T. S. 6. 


3 
T. S. C. 


4 
S. G. 


5 
S.I. 


6 7 
Tl. A. C. T. 


8 
C. T. T. 


9 
T. A. 


10 

p. 


11 

S. T 


12 
.A. S 


Aug. 19 


1.0673 


17.46 


18.64 


15.87 


14.87 


1.27 


.44 


.18 


1.09 


.42 


17.82 


.82 


Aug. 2.5 


1.0743 


19.26 


20.69 


18.30 


17.03 


1.19 


.47 


.19 


1.00 


.37 


20.14 


.55 


Sept. 1 


1.0771 


20.02 


21.56 


18.98 


17.62 


.85 


.49 


.20 


.65 


.42 


20.54 


1.02 


Sept. 7 


1.0892 


23.20 


25.27 


22.42 


20.58 


.72 


.80 


.32 


.40 


.62 


24.24 


1.03 


Sept. 15 


1.0927 


24.12 


26.36 


23.62 


21.62 


.79 


.76 


.30 


.39 


.45 


25.22 


1.14 


Sept. 22 


1.0984 


25.62 


28.14 


25.71 


23.41 


.60 


.58 


.23 


.37 


.45 


27.11 


1.03 


Sept. 29 


1.1049 


27.33 


30.20 


27.41 


24.81 


.54 


.51 


.20 


.34 


.42 


28.68 


1.52 


ToKay 


























Aug. 19 


1.0598 


15.50 


16.43 


14.41 


13.60 


1.74 


.41 


.16 


1.58 


.29 


16.69 


.26 


Aug. 25 


1.0676 


17.54 


18.73 


15.63 


14.64 


1.24 


.39 


.15 


1.09 


.69 


17.80 


.93 


Sept. 1 


1.0757 


19.65 


21.14 


18.17 


16.89 


.84 


.47 


.19 


.66 


.44 


19.74 


1.40 


Sept. 7 


1.0781 


20.28 


21.86 


19.11 


17.73 


.79 


.45 


.18 


.61 


.37 


20.54 


1.32 


Sept. 15 


1.0785 


20.39 


21.99 


19.26 


17.86 


.74 


.48 


.19 


.55 


.40 


20.69 


1.30 


Sept. 22 


1.0798 


20.73 


22.,38 


20.17 


18.68 


.59 


.51 


.20 


.39 


.36 


21.43 


.95 


Sept. 29 


1.0823 


21.38 


23.14 


20.76 


19.18 


.85 


.58 


.23 


.62 


.28 


22.24 


.90 


Oct. 7 


1.0830 


21.57 


23.36 


20.87 


19.27 


.69 


.63 


.25 


.44 


.42 


22.36 


1.00 


Oct. 14 


1.0851 


22.12 


24.00 


21.53 


19.84 


.65 


.69 


.28 


.38 


.36 


22.96 


1.04 


Oct. 22 


1.0895 


23.28 


25.36 


22.91 


21.03 


.66 


.72 


.29 


.37 


.37 


24.37 


.99 



Burger 



Table 9 — Grape Ripening Tests, 1916 



Variety 
and date 


1 
Sp. gr. 


2 
T. S. G. 


3 
T. S. C. 


4 
S. G. 


5 
S.I. 


6 
TI. A. 


7 8 
C. T. C. T. T 


9 
T. A. 


10 
P. 


11 

S. 


12 
T. S. S 


June 12 


1.0212 


5.48 


5.59 


1.29 


1.55 


2.95 


.55 


.22 


2.73 


.44 


5.27 


.32 


June 19 


1.0195 


5.04 


5.88 


.87 


.88 


2.88 


.51 


.21 


2.67 


.45 


4.51 


1.37 


June 27 


1.0220 


5.69 


5.82 


1.25 


1.28 


2.94 


.33 


.13 


2.81 


.45 


4.87 


.95 


July 7 


1.0220 


5.69 


5.82 


1.11 


1.28 


2.98 


.49 


.20 


2.78 


.31 


4.86 


.96 


July 10 


1.0200 


5.17 


5.27 


.93 


.95 


3.32 


.57 


.23 


3.09 


.37 


4.97 


.30 


July 19 


1.0205 


5.30 


5.41 


1.03 


1.05 


3.13 


.55 


.22 


2.91 


.35 


4.86 


.55 


July 27 


1.0225 


5.82 


5.95 


1.13 


1.15 


2.93 


.48 


.19 


2.74 


.34 


4.71 


1.24 


Aug. 3 


1.0258 


6.67 


6.84 


2.14 


2.19 


2.71 


.63 


.25 


2.46 


.40 


5.68 


1.16 


Aug. 7 


1.0330 


8.53 


8.83 


3.36 


3.46 


2.67 


.87 


.35 


2.32 


.47 


7.12 


1.21 


Aug. 16 


1.0391 


10.11 


10.51 


5.90 


6.13 


2.41 


.95 


.38 


2.03 


.46 


9.57 


.94 


Aug. 23 


1.0422 


10.92 


11.38 


6.03 


6.27 


2.10 


.98 


.39 


1.71 


.63 


9.59 


1.89 


Aug. 30 


1.0529 


13.70 


14.42 


9.95 


10.42 


1.15 


1.03 


.41 


.74 


.49 


12.70 


1.72 


Sept. 5 


1.0645 


16.73 


17.81 


14.51 


1.5.43 


1.01 


1.07 


.43 


.68 


.61 


17.79 


.02 


Sept. 12 


1.0717 


18.61 


19.94 


16.27 


17.36 


.95 


.98 


.39 


.56 


.82 


19.72 


.22 


Sept. 20 


1.0765 


19.86 


21.37 


17.44 


18.73 


.87 


1.06 


.42 


.45 


.62 


20.86 


.51 


Sept. 26 


1.0808 


20.99 


22.68 


18.48 


19.99 


.81 


1.01 


.40 


.41 


.83 


22.24 


.44 


Cornichon 


























June 12 


1.0202 


5.22 


5.32 


.91 


.93 


3.15 


.64 


.26 


2.89 


.32 


4.78 


.54 


June 19 


1.0200 


5.17 


5.27 


.86 


.88 


2.96 


.62 


.25 


2.71 


.42 


4.63 


.64 


June 27 


1.0193 


4.99 


5. OS 


.84 


.86 


2.89 


.39 


.16 


2.73 


.56 


4.54 


.44 


July 7 


1.0201 


5.19 


5.29 


.87 


.89 


2.88 


.44 


.18 


2.70 


.52 


4..55 


.74 


July 10 


1.0206 


5.32 


5.43 


.85 


.87 


3.27 


.54 


22 


3.05 


.53 


4.99 


.44 


July 19 


1.0225 


5.82 


5.95 


1.28 


1.30 


3.11 


.57 


.23 


2.88 


..55 


5.30 


.65 


July 27 


1.0242 


6.25 


6.40 


1.63 


1.66 


2.94 


.54 


oo 


2 72 


.44 


5.26 


.14 


Aug. 3 


1.0373 


9.65 


10.00 


5.00 


5.19 


2.87 


.59 


.24 


2.63 


.56 


8.97 


1.03 



[1141 



CHEMIC.il COMl'OSITION OF CUAl'KS 



43-) 



Table 9 — {Continued) 



Variety 
and date 


1 

Sp. gr. 


2 
T. s'. G. 


3 
T. S. C. 


4 

S. fi. 


S.''l. 


(i 
Tl. A. 


C. T. C 


8 
T.T 


I) 
T. A. 


10 

V. 


11 12 
S. T. A. S 


Aug. 7 


l.OS?.^ 


9.70 


10.06 


5.28 


5.48 


2.79 


.65 


.26 


2.53 


.66 


9.32 


.64 


Aug. 16 


1.0434 


11.23 


11.71 


6.30 


6.57 


2.75 


1.06 


.43 


2.32 


.53 


10.48 


1.23 


Aug. 23 


1.0635 


16.47 


17.51 


12.19 


12.96 


1.85 


1.06 


.43 


1.42 


.58 


16.02 


1.49 


Aug. 30 


1.06S5 


17.77 


18.97 


14.75 


15.61 


1.16 


1.10 


.44 


.72 


.63 


18.06 


.91 


Sept. 5 


1.0694 


18.01 


19.25 


15.03 


16.07 


.93 


.90 


.36 


.57 


.58 


18.12 


1.13 


Sept. 12 


1.0757 


19.65 


21.09 


16.37 


17.60 


.87 


1.14 


.46 


.41 


.78 


19.97 


1.12 



Sept. 20 1.0786 20.41 22.00 17.52 18.88 
Sept. 26 1.082S 21..52 23.30 18..52 20.03 



.84 .94 .37 .44 .59 20.85 1.15 
.72 .83 .,33 .39 .85 22.10 1.20 



Muscat 



June 12 


1.0203 


5.25 


5.35 


.91 


.93 


2.93 


.65 


.26 


2.71 


.38 


4.67 


.68 


June 19 


1.0199 


5.14 


5.24 


.70 


.72 


3.37 


.63 


25 


3.12 


.44 


4.91 


.33 


June 27 


1.0210 


5.43 


5.54 


1.33 


1.36 


3.33 


.48 


19 


3.14 


.49 


5.47 


.07 


July 7 


1.0210 


5.43 


5.54 


1.63 


1.66 


3.32 


.54 


22 


3.10 


.45 


5.75 


.21 


July 10 


1.0195 


5.04 


5.14 


1.33 


1.36 


3.60 


.55 


22 


3.38 


.36 


5.65 


.51 


July 19 


1.0251 


6.49 


6.65 


2.55 


2.61 


3.40 


.58 


23 


3.17 


.49 


6.85 


.20 


July 27 


1.0308 


7.97 


8.22 


3.56 


3.67 


2.67 


.66 


26 


2.01 


.45 


6.79 


1.43 


Aug. 3 


1.0488 


12.64 


13.26 


9.72 


10.19 


1.77 


.68 


27 


1.50 


.46 


12.83 


.43 


Aug. 7 


1.0582 


15.68 


16.58 


12.72 


13.53 


1.60 


.73 


29 


1.31 


.55 


16.12 


.46 


Aug. 16 


1.0803 


20.86 


22.53 


16.81 


18.15 


1.16 


.94 


38 


.78 


.51 


20.38 


1.70 


Aug. 23 


1.0910 


23.67 


25.82 


20.20 


22.04 


.82 


1.04 


42 


.40 


.56 


24.04 


1.78 


Aug. 30 


1.0972 


25.30 


27.75 


21.87 


22.99 


.65 


1.21 


49 


.16 


.58 


25.94 


1.81 


Sept. 5 


1.1023 


26.64 


29.36 


23.28 


24.74 


.60 


1.17 


47 


.13 


.65 


26.69 


2.67 


Sept. 12 


1.1101 


28.70 


31.85 


25.95 


27.83 


.56 


1.35 


54 


.02 


.69 


29.89 


1.96 


Sept. 20 


1.1122 


29.25 


32.72 


26.43 


29.39 


.68 


1.56 


63 


.05 


.58 


31.27 


1.45 


Sept. 26 


1.1133 


29.54 


32.89 


26.68 


29.70 


.56 


1.39 


56 


.00 


.59 


31.57 


1.32 





Table 10 — Catawba 


Grape Ripening 


Tests 








(Table from U. S. Dept. Agric 


Bulletin 335, by 


"W. B. 


Alwood) 




Cataxcha 




















1912: 




















Variety 
and date 


1 

Sp. er. 


T. s". G. 


3 
T. S. C. 


4 

S. I. 


5 
S. G. 


6 
Tl. A. 


7 
0. T. 


8 9 
r. T. T. Days 


Sept. 4 


1.0329 


8.51 


8.84 


3.60 


3.72 


3.68 


.39 


.16 





Sept. 9 


1.0419 


10.84 


11.29 


6.68 


6.96 


3.02 


.41 


.16 


5 


Sept. 12 


1.0515 


13.34 


14.03 


9.35 


9.78 


2.48 


.46 


.18 


8 


Sept. 17 


1.0537 


13.91 


14.66 


10.38 


10.95 


2.12 


.45 


.18 


13 


Sept. 24 


1.0569 


14.74 


15.58 


11.33 


11.96 


1.74 


.53 


.21 


20 


Oct. 1 


1.0614 


15.92 


16.89 


12.75 


13.48 


1.63 


.54 


.22 


27 


Oct. 7 


1.0663 


17.20 


18.34 


13.79 


14.71 


1.53 


.61 


.24 


33 


Oct. 16 


1.0725 


18.82 


20.18 


15.35 


16.46 


1.34 


.61 


.24 


42 


Oct. 23 


1.0716 


18..58 


19.90 


15.01 


16.09 


1.28 


..59 


.24 


47 


Oct. 29 


1.0769 


19.97 


21.50 


16.49 


17.75 


1 22 


.57 


.23 


53 


Nov. 4 


1.0790 


20..'52 


22.14 


16.77 


18.08 


1.28 


.71 


.28 


59 


Nov. 8 


1.0755 


19.60 


21.07 


16.39 


17.61 


1.09 


.52 


.21 


63 



1115] 



436 MISCELLANEOUS STUDIES . 

Curves of Total Solids, Sugar, Total Acid, Free Acid, and Cream 
of Tartar. — In order to present the data in a form in which they may 
be readily studied, graphs have been constructed using time in days 
as abscissae and the above constituents expressed in grams per 100 c.c. 
as ordinates. The curves represent the data for 1914, 1915, and 1916. 
For comparison, curves of the changes in composition of Catawba 
grapes reported by W. B. Alwood in the United States Department 
of Agriculture Bulletin 335 have been included. The acid principles 
have been plotted to a scale five times as great as that used for total 
solids and sugar in order that the variations in acidity might be more 
apparent. 

Discussion of Graphs of Total Solids, Sugar, Total Acid, Cream of 
Tartar, and Free Acid. — (1) Total Solids and Sugar. The data are 
more complete for 1916 than for 1914 or 1915, and include the period 
during which the berries are growing to full size as well as the ripen- 
ing period itself, during which the rapid increase in sugar occurs. 
The curves for 1916, therefore, are of more interest than those for 
1914 and 1915. In the case of the Burger variety, total solids and 
sugar remained constant for approximately forty days after the tests 
were started. There was then a slight rise in these components for 
a period of about ten days. From that point on the rise in total solids 
and sugar was very rapid and fairly uniform. The behavior of the 
Cornichon was very similar. 

The Muscat began ripening about ten days earlier than the Burger 
and Cornichon, and proceeded much more rapidly up to aboiit the 
ninetieth day after the experiment was started. There was then a 
slowing up in the increase in total solids and sugar corresponding to 
the period of over-ripeness. This slower increase in total solids is 
also evident in the curves for Emperor, Muscat, Sultana, and Tokay 
for the 1915 season, and would undoubtedly show in all eases if the 
observations were continued sufficiently. 

The effect of the season upon the rate of ripening is shown by a 
comparison of the Cornichon and Muscat varieties for 1915 and 1916. 
All varieties ripened more slowly in 1915 than in 1916, resulting in 
steeper curves for 1916. However, owing to the fact that sampling 
was started later in 1914 and 1915 than in 1916, the curves for the 
former two years show only the changes taking place during the latter 
half of the ripening period. No very close comparisons therefore can 
be made of the three years. 

The Catawba reported by Alwood, and for which curves appear 



riifii 



CHEMICAL COMPOSITION OF GSAPES 



437 





n. 








Mfll 1 


lG/1 


it^Ch 


OF' 1 


Q/4^ 








a/ 


R= 


ffyfThrit 


rfrrrf 


Trr. /at 


mr/c. n. 


■uLIm'-& 


7/w nf 


Jrir^r 




/^ /ninr.r 




X4- 


n 


T,ih/ 


, V'^'i ' 


7r^/i d/t 


ynr C^/ 


^.•% f^.r 


/nCr.e 




/ 










5 
















y , 








X4 


















^ y 








a 
















y/ 


/ 








a. 


^ 












^ ^ 


"" / 










1^ 












^ 




/ 










lb 








j,i5 


^A*^ 


" 


^^ 














T 






<M^ 




_^^0^ 














M 






A 


^jj^ 




^ 


















^>^ 




=i.rf 


ii^ 
















li. 




^^^ 


lO 


^ ■ 


SX- 


"^^^>< 


^ 


















fi 






-^ "" 


<^ 


















( 


" 










%> 
















1 










^^> 














4 












^"^ 


C^^ 


























"^ 






i 






K 
















^r 


















^ 


3 — -A 


' 1 


7 A 


7 X~ 


!■ J 


5 i 


^ ^ 


^ -sJ 


? 321 3b^ 



r/ME/ND/f^S 




-m — 73 :^ 

T/M£ IN D/F/S 



Fig. 1 — Malaga first and second crops, 1914. 



438 



MISCELLANEOUS STVDIES 




~3 7v 73 To :e3' 
77A<£" /A' C/f-yS 



Fig. 2 — Tokay first and second crops, 1914. 



[1181 



CIIKMHAI. fOMrOSiriOX OF (,I;.I1'KS 



439 




TH fS 

Fig. 3 — Cornii'liou and Emperor, 1915. 



"7^ 73 ^? ■5V~ 3^ 

T/M£ IN DFt-yS 



[1191 



440 



MISCELLANEOUS STUDIES 




Fig. 4^Malaga and Muscat, 1915. 



[1201 



CHEMICAL COiirOlsniUN OF GllAl'ES 



441 




Fig. 5 — Pedro Zuinbon and Sultana, 1915. 



[1211 



442 



illSCELLANEOrS STUDIES 




-m — ^ 

T/ME IN Dft-ys 






it. 



TaiByLMs. 



/J= To'a/ flcld fPer lortcr/c oAd Gea/ v of l^rfar ( S>7J /fer /0O)i 




iz n -^ — 35" 

TIME. IN D/f-ys 

Fig. 6 — Sultanina and Tokay, 1915. 



ri221 



CHKUICAL COMl'OtilTlOS OF Gli.ll'ES 



448 




-2& 3» — ^» 33 — ar 

T//^r /A/ £5/9X5 

Fig. 7 — Burger and Corniclion, 1916. 



TOO — W 



[123] 



444 



MISCELLANEOUS STUDIES 




-^ 72' 35 '^ 3er 

time: IN onys 

Fig. 8— Muscat, 1916. 



BW 






C/fT/JWS/J J9JZ. U.5JDjBJDcpi:-^^/-^3SMnanoGa 



fl= ^rfonc /Jcf /^ ^e r /Jr,ty nm:/ CrfO'^ f^^ Inr tat 
G-. Tnfhl ^nl/d', nnri 3 iiqnr Cym.', f^r ino G/ m 




Fig. 9— Catawba (U. S. Dept. Agric. Bull. 335). 



[1241 



CHEMICAL COMPOSITION OF GRAPES 445 

ill figure 9, ripened more slowly than the Vinifera varieties. For 
example, during a period of fifty days, the total solids increased only 
4 per cent. It can not be said from the data at hand whether this 
slow ripening is due to the conditions under which the grapes were 
grown or to the variety. 

By reference to figures 1 and 2 it may be seen that the general 
form of the ripening curves is the same for the first and for second 
crop. In one case, the Malaga, the curves are almost identical for 
the period common to both, i.e., from 10.6 Bal. to 26.3 Bal., showing 
an equal rate of ripening. In the other, the Tokay, the curve of the 
second crop, from 18.2 Bal. to 24.6 Bal., is much flatter than that of 
the first, indicating a rate of ripening with the latter of about two 
and a half times that of the former. This diiference can be accounted 
for by the cooler weather during the time the second crop Tokay was 
ripening, which was about ten days later than in the case of the second 
crop Malaga. The slower ripening is probably due both to the direct 
effect of the cool weather and to the decreased activity of the leaves 
at lower temperatures. 

(2) ("hanges in Total Acid, Cream of Tartar, and Free Acid. 
Owing to the fact that the analyses were started in 1914 and 1915 
after ripening had commenced, the curves for these years show a 
decrease in acid throughout the period of the tests. In 1916, however, 
a rise in total acid occurred during the growing stage, as shown by 
a rise in the curve during the first thirty days of the experiment. 
Although this rise is not very large, it is quite definite, and occurs 
in all three varieties tested. The rise was most positive in the case 
of the Muscat grape, and amounted to .67 per cent acid as tartaric. 
From the point of maximum acidity, the total decreases slowly until the 
period of rapid ripening sets in. The total acid then decreases very 
rapidly for a time and more or less in proportion to the increase in 
total solids and sugar. As the grapes near maturity, the rate of de- 
crease of total acid becomes less and the total remains practically , 
constant after the grapes have reached maturity. 

The cream of tartar in general increases very slightly during the 
periods of growth and ripening. 

The increase in total acid during the first stages of growth is due 
to increase in the free acid. Since the cream of tartar remains almost 
constant throughout the ripening period, the curve of the free acid 
is practically parallel with that of the total acid. 

As the grapes approach maturity, the cream of tartar calculated as 



[125] 



446 



MISCELLANEOVS STUDIES 



tartaric acid approaches the total acid, and in one case, (Musct, 1916), 
actually became equal to the total acid, indicating that in this instance 
no free acid remained. 

Second crop grapes were found to be higher in free acid than 
first crop grapes of the same total solids and sugar content. The 
Catawba grape grown under eastern conditions (fig. 9) exhibits rela- 
tively high free acid. Alwood** has found this free acidity in eastern 
grapes to be due largely to malic acid. No attempt was made in the 
analyses of the California samples to identify the various acids making 
up the free acidity which was calculated as tartaric acid. 

Mean Differences Between Total Solids and Sugar. — The following 
table contains figures representing the differences between total solids 
and sugar at the various percentages of total solids indicated at the 
tops of the columns. The data represent a range of total solids from 
5 per cent to 30 per cent. The figures were taken from the data 
reported in tables 7 to 9, and represent several varieties of grapes. 
Only a few determinations of total solids and sugar were available 
for the lower concentrations (5 per cent to 1.5 per cent), and therefore 
the figures for this range may not represent averages so accurately 
as the figiires above 15 per cent total solids. 

Between 5 per cent and 11 per cent solids, the average difference 
between total solids and sugar remains practically constant. From 
11 per cent to 17 per cent total solids, the mean difference decreases 
quite rapidly. Prom 17 per cent to 30 per cent, the difference remains 
fairly constant. The variations noted after 17 ])er cent total solids 



T 










Mimn 1 


'llU.StSti 


/7*f.T 


"irtn 


rrr 


^ofnl 


2a/M: 










> 






aacL2i 






,■7 m 


i 7)0 ;, 


' 7^A 


/ <lJ 


d^ 




4 


^~~^ 


'■^ 


'\. 






















i 






\ 




















^ 


h 






s 






















S 










^•^^^^ ' 


■^^-( 




^ 


^ 


^ y 


.^ 


<e 


I 














i 


"H 


■^ 








\i 
























/ 


























































5 


' 5 


U^ 


i%_^ 


•■9"'=^. 




^ /; 


/ X) 


X 


J ^~ 


X 


7 Xi 


\ 37 



Fig. 10 — Mean dififerences between total solids and sugar between 5 per cent 
and 30 per cent total solids. 



6 XJ. S. Dept. Agric. Bull. 335. 



CIIKMICM. CUMrUNiriOX OF OUAI'KH 



447 



>(>' 


1 




5 




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1^ 








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to 


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to O -<1 CO -^ CO O CO 



w 



to to to to CO CO JO 
CD •<) bo -^l CO CO to 



cotococototocotocototo >-• 

O CO to CD bi --3 I-' CO CO CO bi ''^ 

CO to CO to to to CO to CO to W to 

CO **- o bo hp- rf*- H* ^ to ^ en ° 



tf' to to to to CO to to to to CO J-- to 

O "no OT '^ ^ CO If* <D ^ CO H-* '-~5 *"* 

COtOCOtOtOtOtOtOCOtO 10 

: o^obobiQo'ojuibio 



to 



to CO CO to to CO 
^ o OS bi *rf^ o 



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cototoi-*totocotoco M 
bicn--icobobicnb>to 

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i rfifc rfk. oi I*^ '^ en bi bi 

to to to to to to 

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, to to to ^ 

I i : i I : '** b> no 

to CO to ta 

i : : : ■ . : co bo bo * 



O 



CO 
no 



448 



MISCELLANEOUS STUDIES 



was reached are probably within the experimental error. The large 
difference between the total solids and sugar noted during the first 
stages of ripening is no doubt due to the high acid content of the 
unripe grapes. The fact that the difference remains fairly constant 
after the grapes have become mature is to be expected, because the 
cream of tartar, total acid, and protein remain fairly constant as 
maturity is approached and during the periods of maturity and over- 
ripeness. 




-?» 7t> 33 7» yn to 7n Ttr 

Fig. 11 — Variation in uon-coagulable protein content for three varieties, 1916. 



Protein. — The total nitrogen content of the various samples was 
multiplied by 6.25 to convert it into its protein equivalent. Owing 
to the fact that the samples were sterilized by heat and filtered before 
analysis, the figures represent only the protein not coagulated by heat. 

The curves. show that there is a slow increase in protein content 
during growth and ripening and the greatest increase occurs during 
the period of most rapid increase of sugar and most rapid decrease 
of acid. The increase amounted to about .2 per cent in the case of the 
Muscat and .6 per cent in the ease of the Cornichon. The increase 
seems to be quite definite, although the protein curves are not so 
i-egular as those of total solids, sugar, and total acid. 



[1281 



CHEMICAL COMPOSITION Of GUAl'KS 449 



Summary op Changes in Must of Grapes During Growth and 
Ripening op Berries 

1. Total Solids. — The total solids remain fairly constant during 
the period of growth, corresponding to the period between setting of 
the berries and the time at which the berries have reached almost 
full size but are still hard and green. From this point on, there is a 
rapid increase in total solids due to increase in sugar. 

After the period usually considered as full maturity is reached, 
the increase in total solids is slow. The question may be raised as to 
whether this last increase is due to an actual synthesis and secretion 
of sugar or other solids, or simply to evaporation of water. The fact 
that there is no change in the curve of the acid decrease at this time 
indicates that the same processes are continuing and that the increased 
Balling degree represents an actual increase of solids. This view is 
fortified by observations regarding the increase of weight of solids 
during the ripening of raisin grapes. It has been shown that the 
weight of dried grapes shows a continuous increase up to the highest 
degree observed, 28.75 Balling.^ 

' 2. Sugar.- — The total sugar during the growth period comprises 
only a small amount of the total solids. During ripening, the sugar 
rapidly increases and then constitutes a much greater proportion. 
During ripening, the sugar curve follows the total solids curve closely. 
It is more or less the mirror image of the total acid curve multiplied 
by five, i.e., increases as the acid decreases. 

3. Total Acid and Free Acid. — During the early stages of the 
growth of the berries, the acidity increases owing to an increase of 
free acid. This is a fact that the authors have not found mentioned 
in the literature. During ripening, the total and free acid rapidly 
decrease. After maturity is reached, the decrease is very slow. 

4. Cream of Tartar. — There is a very slow, but usually fairly defi- 
nite, increase in cream of tartar during ripening. This increase is 
very much less than the decrease in free acid, and therefore can not 
account for any great part of this decrease. 



' Bioletti, Frederic T., Relation of the maturity of the grapes to the quantity and 
quality of the raisins. Proc. Inter. Cong, of Viticulture, San Francisco, 1915, 
pp. 307-314. 



[129] 



450 MISCELLANEOUS STUDIES 

5. Protein. — The protein not coagulated by heat increased defi- 
nitely during growth and ripening, although the increase was not so 
regular nor so marked as the increase in sugar or the decrease in total 
acid. 

6. Difference Between Total Solids and Sugar. — This factor re- 
mained constant for the lower percentages of total solids, decreased 
during the rapid ripening stage, and remained constant through 
maturity and over-ripeness. 



[1301 



I 



LIBRARY OF CONGRESS 



003 080 442 9 




